How do I move from the UK to Belgium?

Honestly. Since Brexit, UK nationals are treated as non-EU nationals, so they need a visa or residence permit to live in Belgium for more than 90 days. You need to check if he needs a single permit if he's looking for work here. He can only stay 90 days for holidays. He'll need to apply for the right visa at the embassy in the UK well in advance. Once we got to our village in Wallonia, we had to register at the commune within 8 days of arriving. It was much easier for us because the Belgian authorities had already officially recognized our marriage back home, which helped with his residency card application. Make sure you have the criminal record certificate ready too.