The Port Authority has an office at the extreme southern point of the island in a small wooden house. Three men work there and are helpful. They have copies of the Mariners'Handbook, It's a 60 page study guide for the Captains Licences test. The book cost 15. bz dollars. You'll also have a piratical exam driving a boat. Both test are fairly simple and straightforward. Heads up on driving your boat to take the exam, his first question will be ,'Who captained this boat down here?' it goes downhill from there if you can't produce someone with a licences that brought it to the test site.
Like all the permits and permissions you get while living in Belize you'll run into the need for a lot of patience and a good sense of humor or I promise you will crash and burn. It's magical to simply say, 'I don't know how to do this ,can you help me.' and The kiss of death comes shortly after you say 'Well, that's how we do it in the States.'