A foreigner is generally considered a Belgian tax resident when their main home or centre of economic interests is in Belgium. In practice, registering at the local town hall often triggers resident tax status, meaning worldwide income becomes taxable in Belgium.

However, this presumption can be challenged. If your stay is temporary and you can demonstrate that your personal and economic ties remain abroad, it may still be possible to qualify as a non-resident taxpayer—provided you have not yet filed a resident tax return. For non-residents, only Belgian-source income is taxable, such as:

• Employment income linked to Belgium (e.g. salary cost borne by a Belgian entity or presence exceeding 183 days in specific employment/treaty contexts)
• Income from a fixed base or business activity in Belgium
• Belgian real estate or local investment income

Important for married couples / legal cohabitants:
If you live together in Belgium, you will automatically be treated as Belgian tax residents. In this case, Belgium is considered your family residence, and non-resident status is no longer possible.

Given the complexity, a case-by-case assessment is essential to optimise your tax position.

Belgium offers an attractive special tax regime for inbound taxpayers and researchers (since 2022), designed to reduce the cost of international assignments.

Key benefits include:

• Up to 35% of gross salary tax-free as expatriation allowance
• Tax-free reimbursements for school fees, relocation and installation costs
• These allowances are also (mainly) exempt from Belgian social security contributions
• Possibility to exclude certain foreign workdays from Belgian taxation
• The regime remains applicable when changing employer (subject to conditions) and is valid for a duration of 5 years, with a possible 3-year extension (maximum 8 years)

To qualify, the inbound taxpayer is subject to a minimum gross salary threshold (for inbound researchers no salary threshold applied, but it requires a relevant degree (STEM) or 10 years’ experience). In both cases, strict conditions apply, including but not limited to recruitment from abroad and not living within 150km of the Belgian border during the 60 months prior to the start of the employment in Belgium. Timing is crucial: the application must be filed within 3 months of the start of employment.

Given the complexity and strict eligibility criteria, proper structuring and timely application are essential to fully benefit from the regime.

EU/EEA nationals do not need a work permit.

Most non-EU nationals need both a work authorisation (usually via a Single Permit), and a long-stay visa (Type D) to enter Belgium. The application is filed by the employer and once approved by both the immigration office and the regional authorities, the visa can be applied for at the Belgian Embassy in the home country. The processing time equals on average 5 to 6 months.

The exact process depends on nationality, duration of work, and type of employment.

The Single Permit is a combined work and residence permit required for non-EU nationals working in Belgium for more than 90 days. It allows non-EU/EEA nationals to live and work in Belgium.

Upon arrival in Belgium, the registration at the town hall is required to obtain a temporary document allowing you to start working.

The procedure is strictly document-driven—missing or incorrect documents can delay the process. The permit is typically issued for a limited duration.

Given the administrative complexity and tight timelines, proper preparation and follow-up are key to avoiding delays.

Under the lex loci laboris principle, employees working in Belgium are subject to Belgian social security, regardless of their nationality or where the employer is based.

Exceptions apply for temporary assignments. If the employee remains covered by a foreign social security system (e.g. via an A1 certificate in the EU or a bilateral agreement), Belgian contributions may not be due.

A Limosa declaration is typically required in such cases to notify the Belgian authorities of the temporary postingand confirm the applicable foreign system. A Limosa declaration does not replace social security obligations, it is only a notification tool.

The applicable social security regime must be assessed separately and incorrect assumptions can lead to significant fines and retroactive contributions.

Given the complexity, each situation should be reviewed case by case to ensure compliance and avoid risks.