The rules for leaving Belgium
Belgium has no residency-opinion request. Residency is a question of fact — domicile or seat of wealth — backed by a legal presumption tied to the National Register. You deregister at your commune, file a special return for the departure year within three months, and carry the evidence in case FPS Finance asks. Getting the file right before you leave is what protects you later.
Domicile, or seat of wealth, in Belgium.
You are a Belgian resident for personal income tax if you have established your domicile in Belgium or, failing that, the primary location of your assets (the seat of your wealth) in Belgium. Domicile is where you effectively and permanently reside; the seat of wealth is the centre of your economic activities or financial interests. Both are assessed on the facts, not on a day count.
Anyone entered in the National Register is presumed resident unless the contrary is proved — which is why deregistration at the commune matters, and why it is not on its own enough.
FPS Finance: leaving Belgium — tax return ↗Couples are resident where the household is.
For married couples and legal cohabitants the tax domicile is where the household is established. FPS Finance's own guidance puts it plainly: both spouses are either both liable to personal income tax, or both liable to non-resident income tax if the household is established abroad. A spouse or partner who stays in the family home in Belgium keeps you resident, whatever your own travel pattern looks like.
FPS Finance: leaving Belgium — tax return ↗An advance ruling is the closest thing to an opinion.
The Service for Advance Decisions (Service des Décisions Anticipées / Dienst Voorafgaande Beslissingen) can issue a binding advance ruling on how the tax law applies to a specific planned situation, generally valid for five years and preceded by a prefiling. It is used for structured questions — the 2026 exit rule on financial assets, a company or a trust — rather than as a general 'am I still resident' opinion. FPS Finance issues no residency certificate for leavers; your new country's authority issues the certificate of residence you will rely on under a treaty.
Service for Advance Decisions (ruling.be) ↗The departure year has its own special return.
A resident who leaves Belgium during the year files a special return (déclaration spéciale / aangifte speciaal) covering 1 January to the date of departure, within three months of leaving — you ask your tax office for it rather than waiting for the normal form. From the following year you file the non-resident income tax return only if you still have Belgian-source income: for income year 2025 the filing window is 3 September to 20 November 2026, on MyMinfin or on paper.
FPS Finance: non-resident income tax return ↗The 2026 exit rule,
without the guesswork.
Until 2025 Belgium taxed no individual on leaving. That changed with the Law of 6 April 2026 introducing the tax on capital gains on financial assets, applicable to gains realised from 1 January 2026: a flat 10% on shares, bonds, funds, crypto and similar assets above a €10,000 annual exemption, with a separate regime for holdings of at least 20%. The law contains an exit rule: when you cease to be a Belgian resident, your financial assets are treated as disposed of, on the gain accrued since 1 January 2026 (or since acquisition, if later). Moving to an EEA state or a treaty country with exchange of information and recovery assistance gives an automatic deferral; elsewhere you ask for deferral and provide a guarantee. If you do not sell within 24 months, the exit tax is definitively cancelled; sell inside that window and it falls due. Each of these is a number, and a decision, that belongs in your file before you leave.
FPS Finance: tax on capital gains on financial assets ↗Why the facts matter more than the flight
Belgian tax obligations depend on residency. Residents declare worldwide income, whether exempt under a treaty or not; non-residents declare Belgian-source income only — property, Belgian pensions and Belgian professional income. FPS Finance decides which you are by looking at where your domicile and your household actually are, not at your departure date.
Where is your home?
Domicile means the place where you effectively and permanently reside. Whether you sold, let out or kept your Belgian home available is the heaviest fact.
Where is your household?
For married couples and legal cohabitants the tax domicile is where the household is established. A partner staying in Belgium needs an explanation, not silence.
Where is the seat of your wealth?
Bank accounts, portfolios, a company you manage, rental property and where you are registered tell the story the test is asking about.
Read FPS Finance's guidance on leaving Belgium ↗
Official sources checked 8 September 2026. Rules and thresholds change; confirm before you rely on them.
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