Biscayne National Park is one of the least-crowded parks in America's national park system, probably because its main attractions are kind of difficult to reach. It's not a question of being remote -- it's so close to Miami, you can do it as a day trip -- but more about being hidden from view. Aboveground, you'll see only a no-big-deal strip of mangrove shoreline and 44 barrier islands, most of them mere specks off of South Florida's east coast. But beneath the surface lies the world's third-longest coral reef, an aquatic universe pulsing with multicolored life. All it takes is strapping on a snorkel and fins for kids to be able to cruise around this tropical paradise, encountering bright parrotfish and angelfish, gently rocking sea fans, and coral labyrinths.
The clear, warm waters of Biscayne National Park are packed with reef fish, rays, moray eels, jellyfish, anemones, sponges, even sea turtles and dolphins -- some 512 species, all told, in this 173,000-acre expanse. On top of that, an underwater trail identifies six shipwrecks off of Elliott Key; mooring buoys point the way to the wrecks, with waterproof cards attached to tell the kids what they're seeing. You can rent equipment at the full-service dive shop at the park's mainland entrance at Convoy Point, and if you don't have your own boat, you can take a 3-hour snorkeling or diving tour operated every afternoon by Biscayne National Underwater Park, Inc., 9700 SW 328th St. (tel. 305/230-1100; www.biscayneunderwater.com); you'll either stick to the bay or head out to the reefs, depending on the very changeable weather. Even beginning snorkelers will get a satisfying eyeful.
The mainland entrance is 9 miles east of Homestead, off U.S. 1; a small beach and marina are nearby, but the rest of the park is accessible only by boat, either your own or the park concession's water transport (tel. 305/230-1100). Few of the park's islands are even open to visitors; the two most popular are Elliott Key and Boca Chita Key, which can be reached by launch from the visitor center. Both islands have campsites (call the park ranger at tel. 305/230-7275 for information on permits and camping fees) and places to moor your boat; Elliott Key also has an interesting nature trail, and Boca Chita, once an exclusive haven for yachters, has some restored historic buildings.
If you prefer not to dive, take the wimp's way out and view the underwater sights on a 3-hour glass-bottom boat tour offered by Biscayne National Underwater Park, Inc., departing at 10am and at 1:30pm. Reservations are almost always necessary.
Nearest Airport: Miami International, 40 miles.
Where to Stay: $$ Indian Creek Hotel, 2727 Indian Creek Dr., Miami Beach (tel. 800/491-2772 or 305/531-2727; www.indiancreekhotel.com). $$$ Ritz-Carlton Key Biscayne, 455 Grand Bay Dr., Key Biscayne (tel. 800/542-8680 or 305/365-4500; www.ritzcarlton.com).