Identification Numbers in Belgium

How to obtain the Belgian identification numbers KBO/BCE, VAT number (TVA/BTW), Limosa, NISS number, and EORI number? We explain their purpose.

When you set up a business in Belgium, you will encounter several key identification numbers. These numbers are not just a formality—they serve important functions within the legal and administrative system, facilitating contact with authorities and business partners. In this guide, we will clearly explain the most important ones: the KBO/BCE number, the VAT number (TVA/BTW), the NISS number, and the EORI number. You will learn what each one is, who must obtain it, how to do so, where these numbers are used in practice, and what their formats look like. Finally, we will present a brief story of entrepreneur Mr. Jan, which shows how all these identifiers cooperate in the daily running of a business in Belgium.

KBO/BCE Number (Banque-Carrefour des Entreprises / Kruispuntbank van Ondernemingen)

What it is and its function: 

The KBO (Dutch: Kruispuntbank van Ondernemingen) or BCE (French: Banque-Carrefour des Entreprises) is the central database for businesses in Belgium, serving as the national company register. Upon registering a business activity in the KBO, every company (whether a corporation or a sole proprietorship) receives a unique enterprise number. This is a 10-digit identification code that consolidates basic information about all legal entities and self-employed individuals in Belgium. The KBO/BCE number streamlines information exchange with the administration—it is used to identify the company across all offices and registers, allowing data to be submitted only once, while state bodies exchange the necessary information among themselves. In practice, this increases the efficiency of state service for entrepreneurs and simplifies the completion of administrative duties.

Who and when must obtain it:

The obligation to obtain a KBO number applies to every entrepreneur starting a business in Belgium—regardless of the company size, legal form, or type of activity. All business activities must be registered in the KBO database, no later than the day activity commences​. This applies to both commercial companies and individual physical persons operating as sole proprietorships (self-employed). There is no general exemption from registration—even if you run a small-scale side business or supplementary activity alongside full-time employment, formal registration and obtaining an enterprise number is necessary for legal operation. Failure to register a company in the KBO may result in administrative penalties, as the company cannot legally conduct business in Belgium without this number.

How the obtaining process works:

Business registration in Belgium usually takes place through an accredited enterprise counter (known as guichet d’entreprise in French or ondernemingsloket in Dutch), which functions as a “one-stop-shop” for business formalities. A natural person starting a business goes to a chosen enterprise counter where they submit an application for entry into the KBO. In the case of a company (legal entity), the deed of incorporation is first drawn up (e.g., at a notary’s office) and registered with the commercial court, and then the company is registered with the KBO—also via an enterprise counter or electronically. The registration application must include required documents (including proof of identity, possibly a business plan or company statutes) and a registration fee. This fee is approximately EUR 100 (the rate is subject to annual indexation) for registering one economic unit. The enterprise counter will also verify whether you meet the conditions for conducting the specific activity (e.g., holding required permits, professional qualifications in regulated industries, etc.). As part of the registration process, your company’s data is transferred to relevant institutions—including the tax administration and social insurance—to obtain their approval. Once all formalities are completed and the application is approved, the KBO assigns a unique identification number to your company. You will be informed about the assignment of the number, and from that moment, your company officially appears in the enterprise register.

Where and in what context it is used:

The KBO/BCE number serves as the universal company identifier and is used in every official context related to business activity. You must include this number on all company documents—including invoices, contracts, offers, purchase orders, and even on letterheads, the website, or advertisements. This allows contractors, clients, and state bodies to easily verify the existence and details of your company in the register. The KBO number is also required when filling out various official forms and declarations: it will be needed for submissions to the tax office, when applying for permits or licenses, and in dealings with the Social Insurance Institution (e.g., when registering as an employer or reporting employees). Additionally, this number may appear on company vehicles (for certain activities, such as itinerant trade or construction services, marking the vehicle with the company number is required) and on the signage of the enterprise’s headquarters. In summary, the KBO number accompanies you in nearly every business interaction—it ensures transparency and trust by showing that your company is registered and operating legally.

Number format:

The Belgian enterprise number consists of 10 digits. It is often written with dots for readability, in the format XXX.XXX.XXX (nine digits) or with a leading zero as 0XX.XXX.XXX (ten digits total). For example, the number may look like 0123.456.789. This ten-digit code is unique to each entity—no two companies have the same number. It is worth noting that the current system unified previous commercial and VAT numbers: in the past, company registration numbers and VAT numbers in Belgium were separate, but since the creation of the KBO, they have become one string of digits. Thanks to this, one enterprise number serves multiple functions (it is the primary company number, and after activation, it can also serve as the VAT number—more on this below). Note: If a company is registered in the KBO but is not subject to VAT, it uses the 10-digit number alone. However, when the company is a VAT payer, this number is used with the country prefix “BE” as part of the VAT number (details in the next section)..

VAT Number (TVA/BTW)

What it is and its function:

The VAT number (from English: Value Added Tax, French: TVA, Dutch: BTW) is the identification number of a taxpayer for the tax on goods and services. In Belgium, VAT, like in other EU countries, is a tax added at every stage of economic turnover. The VAT number serves to identify the company within the VAT settlement system—it allows the tax authority to track the company’s transactions in the context of tax due, and it allows counterparties (especially foreign ones) to verify the company’s tax status.

In practice, holding an active VAT number enables the company to charge VAT on sales invoices and deduct (recover) the VAT paid on business-related purchases. This number is also used in the EU’s VAT Information Exchange System (VIES) to check the validity of counterparty numbers in intra-Community transactions.

Important: Currently in Belgium, a company’s VAT number is almost identical to its KBO number—it differs only by the addition of the country prefix BE before the string of digits. This means that your VAT number is simply “BE + [KBO number].” For example, if the company’s KBO number is 0123.456.789, the VAT number will be presented as BE 0123.456.789. If a company is not subject to VAT (e.g., benefits from the exemption for small businesses or conducts only VAT-exempt activities), then it does not need a separate VAT number—it uses only the KBO number as its identifier.

Who and when must obtain it:

The obligation to register for VAT applies to all entrepreneurs who intend to regularly perform activities subject to VAT (sales of goods or provision of services that are not legally exempt from VAT). The company must have an active VAT number before commencing the sale of taxable goods or services. However, there are exceptions and exemptions that mean not every company needs a VAT number right from the start of the activity::

• Subjective exemption for small companies: elgium applies a simplified VAT exemption system for small entrepreneurs with low turnover. If the company’s anticipated annual turnover does not exceed EUR 25,000 (the value applicable in recent years, subject to valorization—planned to be raised to EUR 35,000 from 2025), the entrepreneur may benefit from a VAT exemption. This means that they do not have to register as a VAT taxpayer—they will not charge VAT to their clients, but in return, they have no right to deduct VAT on purchases. For such an entrepreneur, the KBO number remains the only identification number on invoices (without the BE prefix and without tax settlements). However, this status must be consciously chosen (during business registration, the use of the VAT exemption must be indicated)—exceeding the turnover threshold during the year obligates registration for VAT.
• Objectively exempt activities: Some types of activity are legally exempt from VAT (e.g., medical, educational, financial services). Entrepreneurs performing exclusively VAT-exempt activities do not need a VAT number—similarly, they use only the KBO number. However, if they also plan taxable sales alongside exempt activities, they must register.

Outside of these situations, every new company should obtain a VAT number before making its first taxable sale. This also applies to foreign entities operating in Belgium (non-resident taxpayers)—they are not eligible for the subjective exemption, so even with low turnover, if they make supplies of goods or services subject to Belgian VAT, they must register as a VAT taxpayer in Belgium from the very first transaction.

How the obtaining process works:

Obtaining a VAT number (or VAT identification) is the next step after registering the company with the KBO. First, you must possess an enterprise number, as the VAT registration application refers precisely to this number. The procedure involves filing a VAT registration declaration—standardly, this is Form 604A. Nowadays, the application is filed electronically via the tax administration portal (the e604 application available on the MyMinfin service), which is mandatory for most entrepreneurs.

The application must include, among other things, company details (KBO number, legal form, headquarters address), the anticipated nature of the business (NACE/BEL codes), the chosen VAT settlement system (monthly or quarterly), and potentially an indication of the desire to use the subjective exemption if the conditions are met. Alternatively, VAT registration can be handled through the enterprise counter during company formation or with the help of an accountant—though these are paid services.

The VAT registration must be filed no later than when the taxable activity begins (it is recommended to submit the application shortly after obtaining the KBO number, usually a few days after company registration, so the authority has time to assign the number before the first sale).

Upon positive review of the application, the tax office activates the KBO number as the VAT number—this happens by assigning the status of “VAT taxpayer” to your company in the system. The number remains the same; you simply receive confirmation that it now functions as your VAT number (with the BE prefix). The information regarding the assignment of the VAT number is provided electronically (e.g., via e-Box, the official digital mailbox) or by letter.

From this moment, your VAT number is active, and you can legally issue VAT invoices. It is worth noting that in Belgium, VAT registration is often an integral part of the company formation process—many individuals use the services of an enterprise counter that handles both the KBO entry and the VAT registration simultaneously, so the new company immediately receives a complete package of identification numbers.

Where and in what context it is used:

You must use your active VAT number whenever you operate as a VAT taxpayer—primarily on sales invoices addressed to clients. Belgian law requires the seller’s identification number to be included on the invoice; for a VAT payer, this should be the full format with the country prefix, e.g., TVA BE 0xxx.xxx.xxx (in Wallonia/Brussels) or BTW BE 0xxx.xxx.xxx (in Flanders)​.

The VAT number (or rather its core part, the KBO number) must also appear on all documents where you are legally obligated to provide the company number. For example, if your company letterhead previously showed the KBO number, after VAT registration, it should be supplemented to the form “VAT BE [number]”. This allows counterparties and authorities to immediately see that you are an active taxpayer. You will also use the VAT number when filling out tax declarations (e.g., VAT declarations, which you file monthly or quarterly, logging in with your VAT number) and in correspondence with the tax administration. If you conduct trade across the EU, your VAT number is used in the VIES system—counterparties from other member states can check it online, and you yourself must provide it when making intra-Community transactions (e.g., EU invoices with a 0% rate require the buyer’s and seller’s VAT numbers).

In summary: Everywhere you previously used the enterprise number, as a VAT taxpayer you now use the VAT number—fortunately, it is the same as the company number, differing only by the “VAT BE” designation at the beginning. This way, a single sequence of digits serves a dual role, reducing bureaucracy.

Number format:

The format of the Belgian VAT number is strictly defined by EU standards. Every VAT number begins with the country code BE, followed by the string of 10 digits (constituting the enterprise number). For readability on documents, dots are often used to separate the digits into blocks, e.g., the inscription TVA BE 0123.456.789 is equivalent to BE0123456789. It is important to always provide the full format with the country prefix—in accordance with Belgian regulations, companies should use the format “VAT BE 0123.456.789” on official company documents.

If you run a company registered in Belgium, information about the registering court (RLE) and the branch to which the company belongs is usually added alongside the VAT number (e.g., “RLE Antwerp, Mechelen branch”—though this applies mainly to commercial companies). In the context of the number itself, the most essential thing to remember is that the ten digits of your KBO number form your VAT number, and the only difference in presentation is the addition of BE at the beginning. This number is unique nationwide—unrepeatable both as a company number and a VAT number.

NISS Number (Numéro d’identification à la sécurité sociale / Rijksregisternummer)

What it is and its function: 

The NISS number is the identification number in the Belgian social security system. The acronym NISS comes from the French name Numéro d’Identification à la Sécurité Sociale, and its Dutch equivalent is Rijksregisternummer (national register number). In practice, it is the same number—a unique identifier for every natural person in Belgium, linked to the national population register. The NISS number functions similarly to the Polish PESEL: it unambiguously identifies a person in dealings with state administration, especially in the context of social, health, and tax matters. Everyone who works in Belgium or uses the Belgian social security system has such a number.

For persons registered in Belgium, the NISS number is identical to their national register number—it is located on the back of the Belgian identity card. All data concerning professional careers, insurance, pension contributions, benefits, etc., are assigned precisely to this number. Thanks to NISS, various institutions (e.g., the social insurance body, tax office, health fund) can consistently exchange information about a given person.

For an entrepreneur, the NISS number is important because it identifies you personally as a participant in the system—in contrast to the KBO or VAT numbers, which identify your company. If you run a sole proprietorship, you are still a natural person and, as such, subject to social insurance—your NISS will be used, for example, by the social insurance fund to which you pay contributions (the so-called Caisse d’assurances sociales / Sociaal verzekeringsfonds), or by the tax administration to assign your income tax obligations. In other words, NISS is the number you use in all personal matters in relation to the Belgian state—even when running a company, you act as a citizen towards certain institutions.

Who and when must obtain it:

The NISS number is assigned automatically to every person who enters the Belgian population register or social security system. Belgian citizens receive this number at birth (upon registration of the birth certificate). Foreigners who register their residence in Belgium (e.g., moving permanently or taking up legal employment requiring residence registration) also receive a NISS number as part of the entry into the national register. This number is printed on their residence card (foreigner’s ID) or the E+ card for EU citizens.

In practice, therefore, if you are a Belgian resident entrepreneur or intend to become one, your NISS number will be assigned when completing residence formalities.

There is also a possibility that a person works in Belgium without permanent residence—this applies, for example, to seconded employees or temporary foreign entrepreneurs. Such people may not be listed in the population register, but because they are subject to certain obligations (e.g., work declarations, tax, accident insurance), they need identification. For this purpose, the so-called BIS number is used, which is the equivalent of the NISS number for non-registered persons in Belgium.

The BIS number is assigned by the special BIS register within the Banque Carrefour de la Sécurité Sociale and also takes the form of a unique 11-digit identifier linked to the person.

For example, if you are a Polish entrepreneur not residing in Belgium but performing short-term work there (e.g., within a project), you may receive a BIS number to file required declarations. In practice, obtaining the BIS number occurs, for example, during the registration of an employee or self-employed person in the Limosa system (more on this later) or your client/partner may apply for a NISS/BIS for you for insurance purposes through the belgianIDpro portal. In summary, every person running a business or working in Belgium is assigned a NISS or BIS number—the first for residents, the second for persons outside the population register.

How the obtaining process works:

In contrast to the company or VAT number, there is no separate application procedure for the NISS number—it is assigned ex officio as part of other administrative activities. If you are a Belgian citizen, the NISS number (also called the national register number) was assigned to you at birth and can be found on your ID card. If you are a foreigner settling in Belgium, you receive the number during residence registration at the commune office; the issuance of the residence card with this number may take several weeks, but the number itself is generated upon entry into the register. If, however, you are operating temporarily in Belgium without registration and need to be identified (e.g., as a seconded employee or contractor), the assignment of the BIS number usually occurs incidentally with the first necessity—for example, when filling out the mandatory Limosa declaration for foreigners, the system automatically creates such a number, or your client/partner may submit an online application for NISS/BIS for you for insurance purposes.

The entrepreneur does not have to apply for the NISS number independently; per se, it is an element of a broader procedure (residence or notification). In the case of self-employed foreigners who do not have an NISS, the Belgian social insurance fund (with which they must register to pay contributions) often helps obtain the BIS number from central authorities. For the average user of the system, the most important thing is to know where to find their NISS number—it is available on official identity documents or correspondence from the authorities.

Where and in what context it is used:

The NISS number is used in all matters related to social insurance, taxes, and general administration concerning you as an individual. For example: when registering as a self-employed person in Belgium, you provide your NISS/BIS number so that the social insurance body (ONSS/RSZ) can record you in the system and track your contributions. When you hire employees, you must know their NISS (or BIS) numbers and include them in Dimona declarations (employment registration) and DmfA (quarterly employer declarations)—without the correct employee number, such a declaration cannot be filed.

NISS/BIS numbers are also used when reporting temporary foreign workers in the Limosa system. The NISS number will also be useful when dealing with healthcare services (e.g., if you purchase health insurance from a Belgian health fund, this number will be your patient identifier) or when filing your annual income tax return as an individual.

The Belgian tax authority (FPS Finances) identifies individual taxpayers precisely by the NISS number—it is entered on the income tax declaration. In short, the NISS number is your personal “PESEL” in Belgium—you use it whenever you need to confirm your identity in documents related to your professional activity, but as a person (not a company). Even when running a sole proprietorship, in the background, all contribution and tax obligations are assigned to you via NISS, so it is important to know and protect it (it is a sensitive identification number).

Number format:

The NISS number has a fixed format of 11 digits. The structure of this number is very characteristic: it is based on the date of birth of the person. The scheme is as follows: AATTMMDD-XXX-CC. The first 6 digits are the year, month, and day of birth (YYMMDD). For example: a person born on July 30, 1985, will have the start of the number 85 07 30. The next 3 digits (XXX) are the sequential birth number for that day—odd numbers are assigned to males, and even numbers to females. This means these three digits encode information about the gender (the last digit X is odd for males or even for females) and the order of birth registration for that day (e.g., 001 means the first registered person born that day, 003 the third male, 002 the second female, etc.). The last two digits (CC) are a check digit calculated based on the previous 9 digits—it serves to verify the number’s correctness and falls between 01 and 97.

This structure makes the number unique and simultaneously contains certain data about the owner (date of birth and gender). For foreigners with a BIS number, a similar 11-digit format is used, with the difference that 20 or 40 is added to the portion corresponding to the month of birth (which helps distinguish these numbers from standard resident numbers).

For example, if someone was born in July (07) and has a BIS number, the number might show “27” or “47” instead of “07”. From the user’s perspective, this doesn’t matter much—the important thing is to provide the full 11 digits. The NISS number is usually written separated into blocks of 2-2-2-3-2 (e.g., 85.07.30-123.45), especially on official documents. When providing it in applications or electronic forms, a continuous string of 11 digits without separators is usually sufficient. Since it is a private identifier, it must be protected and provided only in official situations required by law.

EORI Number

What it is and its function:

The EORI number is an identifier essential in the context of international trade—especially for dealings with customs authorities. The acronym EORI stands for Economic Operators Registration and Identification. It is the identification number of an economic operator for customs purposes in the European Union. In practice, if a company plans to import goods from outside the EU or export goods from the EU, it must possess an active EORI number

This number is required when making customs declarations—without EORI, a shipment cannot be formally assigned the status of imported/exported in the common customs system. EORI is unique across the entire EU, meaning one number is valid in all member states. This is a great simplification—a company holding an EORI assigned in one EU country can use it in all customs procedures throughout the Union. Thus, there is no need for multiple registrations in different countries.

In summary: the EORI number is the pass to international goods turnover—it identifies the company in the customs system and allows for efficient handling of customs clearances in export and import.

Who and when must obtain it:

The EORI number is required from every entrepreneur ( or natural person) who intends to make customs declarations related to trade with non-EU countries. If your business activity is limited to services or sales within the EU internal market, you may never need EORI. However, if you plan to import raw materials, products, or equipment, e.g., from the USA, China, the UK, or another non-EU country, you should obtain an EORI number before the first such transaction.

Similarly, an exporter shipping goods from Belgium outside the EU must also possess an EORI. Even a single shipment of goods is subject to these requirements (e.g., a company sending a machine prototype to the USA for a trade fair also needs EORI). Crucially, the requirement to have EORI applies to the customs declarant—the entity on whose behalf the declaration is filed. Usually, the declarant is the owner of the goods or the client commissioning the export/import, even if the clearance is formally handled by a customs agency or courier company on their behalf. You cannot legally conduct exports or imports using an EORI “borrowed” from another entity—the number must belong to the company listed as the sender or recipient of the shipment​.

In other words, you cannot conduct customs operations without your own EORI number, unless you use the services of an intermediary who formally becomes a party to the transaction (which is rare and complicated). It is worth noting that even natural persons can obtain EORI if, for example, they frequently import goods for commercial purposes—however, in the case of ordinary consumers occasionally importing small shipments (of low value), customs authorities usually clear them using the carrier’s EORI number. An entrepreneur planning regular trade in goods to/from third countries should, however, unquestionably possess EORI before the first clearance.

How the obtaining process works: 

Obtaining the EORI number occurs through registration with the customs administration. The competent authority in Belgium is the Federal Public Service Finance (FPS Finances)—Customs and Excise Department. The procedure depends on whether we are an entity established in Belgium or not. If the company is established in Belgium, the EORI application is filed in Belgium—according to regulations, you must register in the country where you are established.

Registration involves filling out a form (marked as Application/BE/EORI/A3 for Belgian entities) and submitting it to the EORI unit of the Belgian customs administration. The application requires basic company details and your KBO or VAT number—this is important because the EORI number will be linked to the existing company number. The procedure is free and quite quick; if the documents are correct, the assignment of the number usually takes no more than 1–2 business days. Confirmation of the EORI assignment can be received via email. In the case of non-EU entities or those without a permanent establishment in the EU, they can also obtain EORI in the first country where they will conduct clearance—for example, a non-EU company submitting goods for clearance in Antwerp can obtain EORI in Belgium (in which case a different form, A4, is used for non-EU entities).

However, for the average Polish entrepreneur operating in Belgium, it is important that if you already have a company registered in Belgium (you have a KBO/VAT number), obtaining EORI involves submitting a short application to the Belgian customs authority. Furthermore, you provide your VAT or KBO number in the form, so your EORI number will be integrated with them—in practice, it will simply be your company number with the “BE” prefix (format explained below). After registration, your EORI is added to the central EU database and is recognized by the customs administrations of all EU member states. You can independently check the validity of your EORI in the public online database—simply enter your company number (without dots), and the system will confirm if the corresponding EORI is active.

The EORI number is assigned indefinitely; it remains valid as long as you conduct business activity requiring customs handling (if you close the company or cease import/export, the number may be deactivated by the authority).

Where and in what context it is used:

You use the EORI number in all customs procedures concerning your company. Above all, you must include it in customs declaration documents—for example, the exporter’s EORI must appear on the export declaration (SAD) when shipping goods outside the EU.

If you import goods, your customs agent or courier company will ask for your EORI to include it in the import declaration and documentation (often with foreign purchases, couriers ask recipients for the EORI number before the goods arrive in the country to expedite clearance). EORI is also required when submitting applications for customs permits, utilizing simplified procedures, operating a customs warehouse, etc. Even when sending a sample or goods to a trade fair in a non-EU country—this is formally an export for which you need EORI. Beyond the customs authorities themselves, the EORI number may also be used in dealings with logistics partners; for instance, a third-country contractor may ask for your EORI to include it on the commercial invoice or consignment note, which facilitates clearance.

In summary, the EORI number is the key to efficient import and export—ensure you have it before importing or exporting goods, as its absence results in delays (customs will not clear the shipment until the importer/exporter obtains EORI).

Number format:

The format of the EORI number throughout the European Union consists of the country code plus a unique string of characters (letters or numbers). In the case of Belgium, the format is simple: BE + the enterprise number. This means that for a company registered in Belgium, its EORI is the letters BE combined with the 10-digit KBO number. For example, if your company has the KBO number 0123.456.789, its EORI will look like this: BE0123456789 (usually written without dots). You avoid any additional suffixes here—the entire number is contained within these 12 characters. It is worth noting that EORI is linked to VAT: upon registration, the customs authority asks for the VAT or KBO number and then links it to the EORI. This means your VAT number automatically corresponds with the EORI number, which is useful, for example, when verifying in systems—often, it is enough to enter the VAT number to check the EORI, and vice versa.

For accuracy, it should be added that in non-typical situations, the format may vary: for example, when a non-EU entity obtains EORI in Belgium, the number may take the format BE + non-EU country code + additional digits, or when a natural person (not a company) applies for EORI, it may contain 12 digits (BE + date of birth, etc.). However, a typical entrepreneur running a business in Belgium will have an EORI consisting exactly of BE and their 10 enterprise number digits. The EORI number is not typically used publicly on company materials (unlike the KBO or VAT number)—we mainly provide it to authorities and trade partners involved in logistics.

Special Cases

Self-employment without registration obligation – is it possible?

In some countries (e.g., Poland), the concept of unregistered minor business activity exists if revenues are below a certain threshold. In Belgium, however, there is no general exemption from the obligation to register business activity. Every person running self-employment (a sole proprietorship) must perform formal registration with the KBO and obtain an enterprise number.

Belgian law treats even the smallest revenue-generating activity as a business activity requiring entry into the register—this applies also to part-time or supplementary activity alongside full-time employment. If you want to legally provide services or sell products in Belgium, you must possess a KBO number. The only activities exempt from the registration obligation are those not considered business activities—e.g., selling used personal items, occasional rental of a private apartment, or other activities of a private nature. However, if an activity shows characteristics of organized, repetitive revenue generation, it should be registered.

It is worth mentioning that while there is no exemption from company registration, there are simplifications for small businesses. An example is the previously mentioned VAT exemption for companies with a turnover up to EUR 25,000 annually—this allows them to avoid many tax obligations (filing VAT declarations, etc.), although they still require a KBO number and must notify the authority of their use of the exemption.

Furthermore, individuals combining self-employment with full-time employment benefit from reliefs in social insurance contributions (lower minimum contribution amounts), but this does not exempt them from business registration. The registration procedure remains mandatory and follows the same rules.

In summary: In Belgium, every entrepreneur, even small-scale self-employed individuals, must be assigned a company identification number in the KBO. There is no equivalent of “unregistered business activity.” Even if you do not need a VAT number (because you are below the threshold or legally exempt), you must have a KBO number and report your activity in the official register. Only then is your activity legal, and you can, for example, issue invoices (even if they are without VAT, they must include the KBO number). Remember that Belgian institutions are quite rigorous regarding the “gray zone”—operating without registration exposes you to fines and problems during potential audits.

Temporary or sole proprietorship activity conducted by an entrepreneur from another EU country

Belgium, as a member of the European Union, respects the principle of freedom to provide services and freedom of establishment. This means that an entrepreneur from another EU country (e.g., from Poland) can temporarily conduct business activity in Belgium without the need to establish a separate company in Belgium. For example, if a Polish entrepreneur has a sole proprietorship and wins a contract to execute a project in Belgium for several months, they can fulfill this contract within the framework of their Polish company. They do not have to register a new business with the KBO or open a branch, provided they do not create a permanent establishment (PE, i.e., a permanent office, branch) in Belgium and operate only temporarily. This is a major simplification—it allows foreign companies to operate in Belgium without dual bureaucracy. However, it is necessary to remember that “bringing” your own business to Belgium does not exempt you from local administrative obligations. Here is what such an EU entrepreneur must consider:

• KBO Registration: If the activity is only temporary and does not create a permanent establishment, you do not make an entry in the KBO as a separate entity. Your company remains registered in its home country (e.g., in CEIDG in Poland) and does not receive a separate Belgian enterprise number. In Belgian registers, you may only appear as a foreign company providing services (e.g., upon registration with the tax office for VAT, the name and address of the Polish company will be noted). Only if your activity in Belgium were to acquire permanent characteristics—e.g., opening an office, warehouse, or conducting uninterrupted activity—would you then need to consider registering a branch with the KBO. For short-term services, you use only your foreign registration number.
• VAT Obligations: Even when operating without a local company, you must comply with Belgian tax regulations. The rule is that a foreign entrepreneur is subject to VAT in Belgium on the same terms as a local entity for activities subject to that tax. Importantly, non-resident entities cannot benefit from the subjective exemption for small companies—the EUR 25,000 exemption limit applies only to companies headquartered in Belgium. Therefore, if a Polish company performs activities in Belgium that would normally be subject to VAT (e.g., services for private individuals, sales of goods in Belgium), it must register for Belgian VAT from the very first transaction. The procedure for such registration takes place through a specialized office for foreign taxpayers (Centre Etrangers ISR in Brussels)—the company will then be assigned a Belgian VAT number (in the format BE + 10 digits). In practice, it often happens that a foreign entrepreneur chooses a local tax representative to help complete the VAT formalities in Belgium. It is worth adding that if the services provided in Belgium are for a company that is a VAT taxpayer in Belgium (B2B), the reverse charge mechanism is often applied—in this case, the Polish service provider does not have to register for VAT in Belgium, as the tax is accounted for by the local purchaser of the service. However, it is necessary to verify each time whether a given transaction qualifies for reverse charge. For legal security in longer projects, foreign entrepreneurs often register for VAT so they can, for example, locally purchase materials with VAT and recover it.
  In summary: If a foreign company performs taxable activities in Belgium (especially sales of goods or services to consumers), it should possess a Belgian VAT number.
• Limosa Declaration: Belgium has introduced the obligation to report the presence and work of foreigners providing services on its territory through the Limosa system. Limosa is an electronic declaration that must be completed by every employer posting an employee to Belgium and every self-employed person arriving in Belgium for work, with certain exceptions. The purpose is to inform Belgian services of the presence of temporary workers from abroad. An EU entrepreneur providing services in Belgium should file a Limosa-1 declaration before commencing work. This applies especially to industries deemed “risk sectors” (high-risk), such as construction, the meat sector, or cleaning, where Limosa for the self-employed is explicitly required by law. Upon filing the declaration, a confirmation (Limosa certificate) is received, which must be presented during an inspection. Failure to file the Limosa notification may result in criminal or administrative penalties for both the foreign entrepreneur and the Belgian entity for whom the work is being performed. In practice, many Belgian companies, when commissioning work from foreign subcontractors, require them to present proof of Limosa registration. For a Polish entrepreneur, the Limosa procedure is relatively simple and can be done online (the Working in Belgium service)—the form is available in English and requires providing, among other things, company details, the period and place of work in Belgium, the type of services, etc.
  In summary: If you operate temporarily in Belgium as a foreign entrepreneur, ensure you have fulfilled the Limosa obligation, as it is often mandatory.
• Social Insurance and NISS Number: The key issue to resolve in cross-border activity is which social security system the entrepreneur is subject to while working abroad. Within the European Union, the rule is that double contributions are not paid—you should be insured in only one country (the one where the work is performed, with certain exceptions). However, for short-term service provision abroad (e.g., a contract for a few months), an EU entrepreneur can remain in their home country’s system based on the A1 form (certificate concerning the applicable legislation). For example, a Polish self-employed person can obtain an A1 form from ZUS confirming that they pay contributions in Poland—in which case, they are exempt from paying contributions in Belgium. Such a person does not become part of the Belgian social security system, so they do not receive a Belgian NISS number, as there is no need for it. They continue to use their Polish insurance number (NIP/PESEL) and pay contributions (pension, health) in Poland. Belgium respects this A1 document. However, if the EU entrepreneur does not have an A1 for some reason (e.g., their activity effectively shifts mainly to Belgium or lasts for a very long time), an obligation to be subject to the Belgian system may arise. In this case, they would have to register with the Belgian social insurance fund for the self-employed, obtain an NISS/BIS number, and pay contributions there (which are quite high). For short-term projects, this scenario is rare—it is assumed that the service provider remains insured in their home country. Therefore, generally, a foreign entrepreneur temporarily in Belgium does not have to “obtain” an NISS number, provided the insurance issue is settled through their home country.
• EORI: If a foreign company transports goods across EU borders in connection with a project in Belgium (e.g., brings equipment, machinery from Poland), the EORI number becomes important. Here is the good news: an EORI number assigned in one EU country is valid in all countries. This means that a Polish entrepreneur who already has a Polish EORI number (PL…) can use it for customs clearances in Belgium without hindrance. Belgian customs authorities recognize foreign EORIs because they are recorded in the common EU database. Therefore, there is no need to apply for a new EORI number in Belgium if you already have one. However, if the Polish company does not have an EORI at all (because they have not imported/exported until now) and needs to import something into Belgium, they can register for EORI in their home country before export or potentially apply for EORI in Belgium as a foreign entity (but the first option is simpler). This way, the customs requirements are met, and no delays are encountered at the EU border.

In summary of this case: An EU entrepreneur can temporarily operate in Belgium based on their home registration, but they should pay attention to local obligations, such as VAT registration (when required) or the Limosa notification. The lack of a Belgian KBO number is not an obstacle for temporary activity, but some formalities must be completed for everything to be legal. For safety, it is advisable to consult the Belgian authority or an advisor beforehand to ensure which notifications are necessary in a specific case.

How These Numbers Work in Practice – Jan’s Story

Finally, let’s look at a short story that demonstrates the practical application of the numbers above in real business. Meet Jan Kowalski, a beginner entrepreneur who decided to set up a company in Belgium. Jan has lived in Antwerp for several years, has family there, and knows the local language. He already has a Belgian NISS number assigned upon residence registration—it appears on his ID card, and Jan uses it, for example, when logging into the tax portal or booking a doctor’s appointment. Jan decided to strike out on his own and start a business as an independent IT consultant.

Company Registration:

Jan goes to a nearby enterprise counter (ondernemingsloket) in Antwerp. He presents his ID, fills out forms, and pays the approximately 100 EUR fee. After a few days, he receives a letter confirming the registration of his sole proprietorship and the assigned KBO number. From now on, Jan is listed in the BCE/KBO register as an entrepreneur. His company number is, say, 0799.999.999. Jan is excited—he prints business cards and proudly places his company name along with the KBO number on each one. This number also appears on his website and email signature, which adds credibility in the eyes of clients (showing the company is officially registered).

First Orders and Invoices:

Initially, Jan assumes his turnover will not be high—he starts alone with a few small orders. He therefore uses the VAT exemption for small companies. Upon registration, he indicated that he anticipates a turnover below EUR 25,000 annually, so he did not have to activate the VAT number. This means fewer formalities at the start. In practice, Jan issues his first invoices for clients in Belgium and includes only the KBO number on them (without the BE prefix and without the VAT rate, with the annotation “subjectively exempt from VAT”). His clients are mainly small local companies who do not mind the lack of VAT on the invoice—they are happy with Jan’s slightly lower service price. Jan remembers, however, to always provide the KBO number on the invoice and all documents—he does this automatically because he knows it is a legal requirement.

Business Growth – VAT:

Over time, Jan’s business takes off. He gains a large corporate client, and his revenues grow quickly as a result. By the end of the year, it turns out that he will exceed the EUR 25,000 limit. Jan, aware of his obligations, notifies the tax office—he electronically files Form 604A for VAT registration. Within a few days, he receives confirmation that his enterprise number has been activated as the VAT number. From this moment, Jan is an active VAT taxpayer. What changes? Now, on all invoices, Jan must add Belgian VAT (21% for IT services) and provide his number in the format VAT BE 0799.999.999. Jan therefore updates his invoice footer—adding “VAT BE” before the existing number. His large client has no problem with this, as they will deduct the VAT anyway. Jan also starts filing quarterly VAT declarations through the Intervat system—he logs in with his VAT number (which is simultaneously the login identifying him in the tax system) and settles the tax. Thanks to having formally registered everything beforehand, he now expands his business without hindrance, and the tax office has him in its records. If Jan had not registered on time, the authority could have detected this itself (e.g., by analyzing his account inflows) and imposed a penalty—but Jan is prudent and acts proactively.

Dealings with Administration and Insurance:

As a self-employed person, Jan must pay social insurance contributions quarterly. He has a contract with a private social fund X, which serves self-employed individuals. Jan notices that his NISS number appears on all documents from the fund—this is the number the fund uses to remit Jan’s contributions to the state system (RSZ/ONSS). The KBO number is not needed here, as the contributions concern Jan as an individual. Similarly, when Jan logs into MyMinfin (the finance portal) to check his income taxes, he uses digital identification linked to the NISS number to do so. He enters this number in the identification box on his annual declaration. We therefore see that Jan operates daily with two numbers: the KBO/VAT number for business purposes and the personal NISS number for tax and contribution purposes. He does not confuse them because each is used in a different context

International Trade – EORI:

After two years, Jan had the idea of expanding his business—he decided to import specialized electronic components from the USA and offer them to his clients in Belgium. Before placing his first order in the States, he already knew he had to handle a customs formality. He used the information on the customs and tax portal and registered his company for EORI. He filled out the form online, providing his VAT number and company details. After a few days, he received an email with his assigned EORI number. He smiled when he saw it, because it turned out to be simply BE0799999999—his company number with the country prefix. Now Jan could import goods without issue. When the package from the USA arrived at Belgian customs clearance, the courier asked Jan for his EORI number. Jan provided BE + 10 digits, which was enough to process the clearance. Customs duties and import VAT were calculated, Jan paid them, and the equipment reached his company. Thanks to EORI, the entire procedure was fast and transparent—Jan’s number appeared on the customs documents as the importer identifier. In the future, when the import business grows, Jan can even independently declare shipments through the customs system, using the EORI number in the field identifying his company.

International Cooperation:

One day, Jan was contacted by his friend from Poland, Piotr, who runs a construction company and won a contract to renovate several historic facades in Belgium. Piotr knew Jan had experience in the Belgian market, so he asked him for advice on formalities. Jan explained the key points: Piotr does not need to establish a Belgian company since he is only coming for 3 months with his own team. However, before starting work, he must file the Limosa declaration—Jan sent him a link to the website where Piotr would file the notification for his construction team. Piotr also ensured all his employees had A1 forms from ZUS to remain subject to Polish contributions. Next, Jan told Piotr about the VAT issue: because Piotr would be working for a private client in Belgium (the townhouse owner), he must register for Belgian VAT as a non-resident. Piotr was initially surprised—”but I have a Polish VAT-EU NIP”—but Jan explained that the reverse charge does not apply to construction work for a private client in Belgium, so Piotr must settle Belgian VAT at the 21% rate. Piotr contacted the Belgian tax office for foreigners and filed an application—as a result, he received a VAT number starting with BE, different from his Polish one (which he left in Poland for settlements there). Now he could legally issue Belgian invoices to his client for each renovation stage. Jan also reminded him about the EORI issue, but Piotr was prepared—having previously imported machinery from England, he already had a Polish EORI, so when he needed to bring some materials to Belgium, he simply used that number (PL…), which worked without issue at the EU border. After the project concluded, Piotr returned to Poland, deregistered from Belgian VAT, and thanked Jan for the valuable tips.

The stories of Jan and Piotr show how all identification numbers cooperate in practice. Jan, running a company in Belgium, uses the KBO number to establish legal presence and build trust; the VAT number to correctly settle taxes on his sales; the NISS number to fulfill his obligations as a citizen (contributions, income taxes); and the EORI number to open himself up to the global market. Piotr, as a foreign entrepreneur, appreciated the simplifications allowing him to operate based on his Polish company, but also had to use several Belgian identifiers (Limosa, VAT, EORI) to meet local requirements. Despite the apparent complexity, each of these numbers has a clearly defined role—together they form a cohesive system that facilitates business.