Places I know you can snorkel for a drink or a meal:
Canoe - Haven't snorkeled there yet, will next week, but understand it's good and it has a sand beach for entry and exit.
Xtabi - Coral shell beach access through a cave. OK snorkelling, cool caves you can swim into, it's Xtabi.
Josephs Cave - Across from Pushcart, you enter through a blow hole to cave bar destroyed by Hurricane Ivan. I would recommend buying drinks from Miss Mae, enjoying the conversation and then asking about using the cave. Don't take any valuables with you as you'll need to leave them in the cave while you snorkel.
Pee Wees - Great bar, beautiful cliff area.
I would also recommend stopping at Home Sweet Home and ask about snorkeling before or after a lunch. 5-800J for a good lunch at a beautiful cliffside restaurant and terrific snorkeling to either the left or the right.
Had awesome high end dinners at the special tables at Rockhouse and Ivan's at Catcha Falling Star. Figure $150 a pop for those though you can spend MUCH less just going in to a regular table.
