John Pennekamp Coral Reef State Park (Key Largo): This is the country's first undersea preserve, with 188 square miles of protected coral reefs. The water throughout much of the park is shallow, so it's an especially great place for snorkelers to see an incredibly vibrant array of coral, including tree-sized elkhorn coral and giant brain coral.

Looe Key National Marine Sanctuary (Bahia Honda State Park): With 5 1/3 square miles of gorgeous coral reef, rock ledges up to 35 feet tall, and a colorful and motley marine community, you may never want to come up for air.

Hutchinson Island: Three popular artificial reefs off this island provide excellent scenery for divers of any level. The USS Rankin, sunk in 120 feet of water in 1988, lies 7 miles east-northeast of the St. Lucie Inlet. The 58-foot-deep Donaldson Reef, located due east of the Gilbert's House of Refuge Museum, consists of a cluster of plumbing fixtures sunk in 58 feet of water. The Ernst Reef, made from old tires, is a 60-foot dive located 4 1/2 miles east-southeast of the St. Lucie inlet. Local dive shops have "tips" on the best spots, and rules and regulations for safe diving.