We spent the day snorkeling at "Pineapple Beach", which is a couple minutes from some big resort that sits on top of a hill just a short walk down the beach. Sorry this isn't more specific, but I'm sure a quick web-search will find you what you're wanting. Our cabbie took us to this beach, and insisted it was some of the best snorkeling on the island (if you also wanted gear rental, jet-ski's, bar, etc.). The water is fairly clear, and there is a "channel" that runs through a large reef, with plenty of fish and neat stuff to see. There's a little bit of undertow near the far edge of the reef, so be careful if you go out really far. On a scale of 1-10, I'de give the snorkeling here a 4, out of all the Caribbean islands I've been to (Cozumel, Grand Cayman, Jamaica, St. Lucia, St. Thomas, St. John, Virging Gorda, Tortola, Barbados, Grenada, Caracao, Antigua, and Isla Margarita). Haven't done Cuba yet....would love to.