Snorkelers and divers should not miss the Keys' most dramatic reefs at the Looe Key National Marine Sanctuary. Here you'll see more than 150 varieties of hard and soft coral -- some centuries old -- as well as every type of tropical fish, including gold and blue parrotfish, moray eels, barracudas, French angels, and tarpon. Looe Key Dive Center, U.S. 1 at MM 27.5, Ramrod Key (tel. 305/872-2215), offers a mind-blowing 5-hour tour aboard a 45-foot catamaran with two shallow 1-hour dives for snorkelers and scuba divers. Snorkelers pay $30; divers with their own equipment pay $40. On Wednesdays and Saturdays, you can do a fascinating dive to the Adolphus Busch, Sr., a shipwreck sunk off Looe Key in 100 feet of water, for $45. Good-quality rentals are available.
