Unlike Pacific Ocean atolls, which are often the crater rings of extinct volcanoes, these atolls were formed over millions of years by a combination of plate tectonics, rising water levels following the last ice age, and millennia of mid-ocean coral growth. Many of the atoll walls drop off steeply for over a thousand feet, while in the central lagoons, the water depths average only 3 to 12m (10-40 ft.).

Most folks come out here to do one of two things: fish or dive. Some do both. Both activities are truly world-class. In broad strokes, fishermen should head to Turneffe Island Atoll, while dedicated and serious divers would probably want to choose Lighthouse Reef Atoll, although there's great diving to be had off Turneffe.

Turneffe Island Atoll

This is the largest of Belize's three ocean atolls, and the largest in the Caribbean Sea. Both the diving and the fishing here are excellent, but the fishing gets a slight nod. The extensive mangrove and saltwater flats are perfect territory for stalking permit, bonefish, snook, and tarpon. Most fishing is done with fly rods, either wading in the flats or from a poled skiff.

Turneffe Island Atoll also boasts scores of world-class wall, coral, and sponge gardens, and drift dive sites. Most of these sites are located around the southern tip of the atoll. Perhaps the most famous dive site here is The Elbow, a jutting coral point with steep drop-offs, huge sponges, and ample fish life. Another popular site is Rendezvous Point, which features several grottoes that divers can swim in and out of, and there's a small modern wreck, the Sayonara, sitting in about 9.1m (30 ft.) of water.

Lighthouse Reef Atoll

Boasting nearly 80km (50 miles) of wall and reef diving, including some of the best and most coveted dive sites in all of the Caribbean, this is a true scuba-diving mecca. As the atoll farthest from shore, its waters are incredibly clear and pristine. The central lagoon of this atoll is some 48km (30 miles) long and around 13km (8 miles) wide at its widest point. In the center, you'll find the world-famous Blue Hole, a perfectly round mid-atoll sinkhole that plunges straight down to a depth of over 122m (400 ft.). You'll see postcards, photos, and T-shirts all over town showing off aerial views of this perfectly round hole in the ocean. Nearly 305m (1,000 ft.) across, the Blue Hole's eroded limestone karst walls and stalactite formations make this a unique and justifiably popular dive site. However, some of the wall and coral garden dives around the outer edges of the atoll are even better. Of these, Half Moon Caye Wall and North Long Caye Wall are consistently considered some of the best clear-water coral wall dives in the world.

Towards the southeastern edge of the atoll is Half Moon Caye National Monument, a combined island and marine reserve. Half Moon Caye itself is the principal nesting ground for the beautiful and odd-looking red-footed booby. These birds are always here in massive numbers. The island is also a prime nesting site for both hawksbill and loggerhead turtles. The Belize Audubon Society (tel. 223-5004; www.belizeaudubon.org) has constructed a small visitor center here, and a wonderful viewing platform near the center of the island. They also allow overnight camping, with prior arrangement. The admission fee is BZ$20 for Half Moon Caye National Monument, and BZ$60 for entrance to the Blue Hole National Monument.

Water conditions here are amazingly consistent, with an average water temperature of around 80°F (27°C), while visibility on the outer atoll walls and reefs easily averages over 30m (100 ft.).

Note: This information was accurate when it was published, but can change without notice. Please be sure to confirm all rates and details directly with the companies in question before planning your trip.