A well-placed snorkel source suggested hitting the waters off Soldier Key, the 1.66-acre island in Biscayne National Park. But park ranger Gary Bremen warns that "snorkeling off Soldier Key is absolutely not allowed. Soldier Key itself is closed to the public for a variety of reasons," including turtle nesting. That doesn't mean there's not great snorkeling in nearby waters. "Snorkeling in Biscayne National Park, well, it's one of those places nobody thinks of because everyone thinks they have to go to Key Largo or south, and they ignore the 50 smaller islands," Bremen says. Because the reefs are about three miles off the islands, a boat is a must. Don't have one? Take a three-hour, ranger-guided tour — you're in the water for an hour, transportation for two hours — for $45. Two boats leave daily, one at 10 a.m. the other at 1 p.m.