A must-do is a half day snorkel with Li'l Alfonse. He is the very best. He is extremely knowledgable of the marine life you will be seeing as well as the coral. I have snorkeled Mexico, U.S. Virgin Islands, British Virgin Islands, Hawaii, Florida and he is the very best. We also took a night snorkel with him, which was awesome. His 1/2-day trips are $25 and night snorkel is $40 (plus $5 for underwater flashlight) You have to have a minimum of 3 people for night snorkel. WE didn't have the third person, so we paid him for that third person just to be able to go. You'll love it.