There are a great many things to do in Ambergris Caye.  Lots of them revolve around water!  There's SCUBA diving (both locally and charters to the outter atolls), snorkeling, parasailing, sailing, the list goes on.

 Then there are the island things to do: sit back and relax on a beach chair, rent a golf cart and putter around, try out some fabulous Caribbean/Mexican food, or go downtown for some souvenir hunting.