Upon departure or a few days earlier, you have to deregister yourself as a resident of Antwerp.
The Immigration Office prefers online deregistration through www.antwerpen.be. The website is in Dutch, however.
Select E-loket. Then type ‘vertrek’ (leaving). You will be able to select ‘vertrek naar het buitenland niet-Belg’ (moving abroad, non-Belgians). Select ‘verdergaan zonder A-profiel’ (continue without A-profile). Select ‘aanvraag starten’ (start application) and complete the electronic form.
The deregistration procedure below is also an option:
After processing, a document called Model 8, proof of deregistration (in Dutch) will be sent to your email address. If you send the document on a later date than the date of departure (= ‘from’ date on the application document), the official date of deregistration will be the date of receipt, not the date of departure.
If you need the proof of deregistration immediately, in order to close your bank account for example, it is best to go to the Immigration Office in Deurne in person and deregister on the spot. A passport picture is required. The Model 8 document will be handed to you immediately.
Do not forget to deregister, otherwise you will continue to be a Belgian resident according to the Belgian authorities. Failure to deregister could have important consequences for visa requirements, taxes, health insurance registration and so on if you return to Belgium in the future.