Deregistration - what to do
Once you know you are leaving the Netherlands, you must deregister from the population register (bevolkingsregister) at the Stadhuis or Gemeente that you received your residency documentation from. You will be asked to hand in your identity card (verblijfsdocument) at the time and provide them with your final date in the Netherlands. This must be done no later than five days before your departure but it would be prudent to start this process well before your departure date. If you do this, you can receive a temporary proof of deregistration and the system will automatically process the final deregistration on the day of your departure.
You should receive written confirmation of your deregistration (vertrekbewijs) automatically in the post. However, check that one will be sent to you and confirm the final address. This confirmation letter is important when you start closing accounts and canceling memberships. Many businesses will ask for proof, or a reason, of closure of the account or membership if you are canceling prior to the agreement expiration date. It is proof that you will no longer be a resident of Netherlands at the stated date. You will have 4 weeks (or 28 days) to leave the country after this period ends.