I can't answer you for sure, but I'm pretty sure they don't care if you're passing through or staying for a couple of days. Here is what we experienced last year when we drove from Mexico through Belize to Guatemala:
Necessary documents
* Passport* Belize Vehicle Import Permit
Costs
* $37.50 Belize Dollars exit fee per personCanceling the Belize Vehicle Import Permit and Tourist Permit:
There is only one border crossing point for cars between Belize and Guatemala, at Benque del Carmen/Melchor de Mencos. To cancel the vehicle permit, first head to Belize immigration where they will stamp your passports for exit. You will then be directed to the Customs desk in the Entry building. This seems pretty weird because you are basically walking into the building the wrong way. Once you reach the desk, present your car permit to the official and request that it be canceled.
For more information on border crossings , see Drive the Americas .
