Will you be absent from your address for more than three months, but plan to return within a year? If so, you do not need to change your address. You do need to report your temporary absence and your return to the city.

If you go abroad for more than one year, you have to let the city know.

Are you going abroad temporarily for more than 90 days? In order to avoid problems upon your return to Belgium, you must apply for your 'right of return'.

Are you not a Belgian and are you moving abroad? Then deregister at the city office.