Finding your way around the Keys isn't hard once you understand the unique address system. Many addresses are simply given as a mile marker (MM) number. The markers themselves are small, green rectangular signs along the side of the Overseas Highway (U.S. 1). They begin with MM 126 a mile south of Florida City and end with MM 0, in Key West. Keys residents use the abbreviation BS for the bay side of U.S. 1 and OS for the ocean side. From Marathon to Key West, residents may also refer to the bay side as the gulf side.

The Keys are divided into four areas: the Upper Keys (MM 106-65), from Key Largo to the Long Key Channel -- including Ocean Reef and North Key Largo, off Card Sound Road and Route 905, respectively; the Middle Keys, from Conch (pronounced konk) Key through Marathon to the south side of the Seven Mile Bridge, including Pigeon Key (MM 65-40); the Lower Keys, from Little Duck Key south through Big Coppitt Key (MM 40-9); and Key West (see the separate Key West Miniguide), from Stock Island through Key West (MM 9-0). The Keys don't end with the highway, however; they stretch another 70 miles west of Key West to the Dry Tortugas.

Here's our highly selective list of the very best things to see and do.



The Upper Keys

The tropical coral reef tract that runs a few miles off the seaward coast accounts for most of the Upper Keys' reputation. This is a diving heaven, thanks to scores of diving options, accessible islands and dive sites, and an established tourism infrastructure.

Yet although diving is king here, fishing, kayaking, and nature touring also draw a large number of tourists. Within 1½ miles of the bay coast lie the islands of Everglades National Park; here naturalists lead ecotours to see one of the world's only saltwater forests, with dolphins, roseate spoonbills, tropical-bird rookeries, and endangered manatees. Though the number of birds has dwindled since John James Audubon captured their beauty on a visit to the Keys, bird-watchers won't be disappointed. And multiple species of fish teem in the shallow waters surrounding the islands, providing food for birds and a challenge to light-tackle fishermen. These same crystal-clear waters attract windsurfers, sailors, and powerboaters.

KEY LARGO HAMMOCKS STATE BOTANICAL SITE. Recent park projects -- rest rooms, information kiosks, and picnic tables -- have made this 2,400-acre park more user friendly and a terrific place to explore the largest remaining stand of the vast West Indian tropical hardwood hammock and mangrove wetland that once covered most of the Keys' upland areas. Nearly 100 species of protected plants and animals coexist here, including the endangered American crocodile, Key Largo wood rat, Key Largo cotton mouse, and Schaus swallowtail butterfly. Interpretive signs describe many of the tropical tree species along a 1¼-mile paved road (2½ mile round-trip) that invites walking, rollerblading, and biking. Rangers point out rare species, tell humorous nature stories, and encourage visitors to taste the fruits of native plants. 1 mi north of U.S. 1 on Rte. 905, OS, North Key Largo, PHONE: 305/451-1202. COST: Free. Daily 8-5, tours Thurs. and Sun. 10.

JOHN PENNEKAMP CORAL REEF STATE PARK. Whenever people talk about the best diving sites in the world, this park is on the short list. The park is home to 78 square miles of coral reefs, sea-grass beds, and mangrove swamps. Its reefs contain 40 of the 52 species of coral in the Atlantic Reef System and more than 650 varieties of fish. Its visitor center has a large central floor-to-ceiling aquarium surrounded by numerous smaller tanks, a video room, and exhibits. A concessionaire rents canoes and powerboats and offers snorkel, dive, and glass-bottom boat trips to the reef. The park also includes short nature trails, two man-made beaches, picnic shelters, a snack bar, and a campground. MM 102.5, OS, Box 487, Key Largo, PHONE: 305/451-1202. COST: $4 per vehicle plus 50¢ per person, $1.50 per pedestrian or bicyclist. Daily 8-sunset. www.dep.state.fl.us/parks

MARITIME MUSEUM OF THE FLORIDA KEYS. Four centuries of shipwreck and salvage history are packed into this small space; visitors stand just inches away from retrieved treasures and artifacts in various stages of preservation. Among the snippets of history are jewels, coins, precious metals, and decorative items from a fleet of treasure ships wrecked by a hurricane in 1715. A bottle exhibit tells Keys history through more than 200 salvaged bottles, dating from as early as the 1600s. The museum is a labor of love, and its primary purpose is preservation. MM 102.5, BS, Key Largo, PHONE: 305/451-6444. COST: $2. Weekdays 10-3.

THEATER OF THE SEA. The lush, tropical 17-acre facility is the second oldest marine mammal facility in the world. Entertaining and educational shows provide insight into conservation issues, natural history, and mammal anatomy, physiology, and husbandry. Visitors can ride a glass-bottom boat and take a four-hour Dolphin Adventure Snorkel Cruise or guided tours to view marine life, raptors, and reptiles. They can visit dolphins and sea lions and participate in animal interaction programs such as Swim with the Dolphins ($110), Swim with Sea Lions ($65), Stingray Reef Swim ($60), and Trainer for a Day ($75). MM 84.5, OS, 84721 Overseas Hwy., Islamorada, PHONE: 305/664-2431. COST: $17.25 (included for participants of interaction programs). Daily 9:30-4. www.theaterofthesea.com

Beach

ANNE'S BEACH. Although recent hurricanes uprooted trees and dramatically changed the shoreline, Anne's Beach on Lower Matecumbe Key remains a popular village park whose sand is best enjoyed at low tide. It also has a ½-mile elevated wooden boardwalk that meanders through a natural wetland hammock. Covered picnic areas along the boardwalk provide a place to rest and enjoy the view. Rest rooms are at the north end. MM 73.5, OS, Islamorada, PHONE: 305/852-2381.

Biking

EQUIPMENT LOCKER SPORT & CYCLE. Single-speed adult and children's bikes can be rented here. Cruisers go for $10 a day, $50 a week. No helmets are available. Tradewinds Plaza, MM 101, OS, Key Largo, PHONE: 305/453-0140.

Boating

HOUSEBOAT VACATIONS OF THE FLORIDA KEYS. Wildlife in the Keys is most active at sunrise and sunset. Be there comfortably at both times with a houseboat. This rental operation has a fleet of 40- to 44-ft boats that accommodate from six to eight people and come fully outfitted with safety equipment and necessities -- except food -- as well as an AM/FM cassette stereo. The three-day minimum runs $595-$890; a week costs $1,025-$1,575. Kayaks, canoes, and 16-ft skiffs are also for hire. MM 85.9, BS, 85944 Overseas Hwy., Islamorada, PHONE: 305/664-4009.

ROBBIE'S BOAT RENTALS & CHARTERS. A 15-ft skiff with a 25-horsepower outboard (the smallest you can charter) is available here for $25 an hour, $70 for four hours, and $90 for the day. Boats up to 27 ft are also available, but there's a two-hour minimum, as are pontoon boats, with a half-day minimum. MM 77.5, BS, 77520 Overseas Hwy., Islamorada, PHONE: 305/664-9814.

TREASURE HARBOR MARINE. Captains Pam and Pete Anderson provide everything you'll need for a vacation at sea -- linens, safety gear, and, best of all, advice on where to find the best beaches, marinas, and lobster sites. You can rent a vessel bareboat or crewed, with sail or with power. Boats range from a 19-ft Cape Dory to a 41-ft custom-built ketch. A 47-ft Tradewind comes with a captain. Rates start at $95 a day, $395 a week. Marina facilities are basic -- water, electric, ice machine, laundry, picnic tables, and shower/rest rooms -- and dockage is only $1 a foot. MM 86.5, OS, 200 Treasure Harbor Dr., Islamorada, PHONE: 305/852-2458 or 800/352-2628.

Fishing

FLORIDA KEYS OUTFITTERS. Long before fly-fishing became a trendy sport, Sandy Moret was fishing the Keys for bonefish, tarpon, and redfish. Now he operates this outfit, home to a store and the Florida Keys Fly Fishing School, which attracts anglers from around the world. Two-day weekend fly-fishing classes, which include classroom instruction, equipment, arrival cocktails, and daily breakfast and lunch, cost $795. Add another $800 for two days of fishing. Guided fishing trips cost $285 for a half day, $425 for a full day. Fishing and accommodations packages (at Cheeca Lodge) are available. MM 82, BS, Islamorada, PHONE: 305/664-5423.

GULF LADY. This 65-ft party boat offers full-day ($50; $55 with rod and reel) and night trips. The boat can be crowded, so call about loads in advance. Whale Harbor Marina, MM 83.5, OS, Islamorada, PHONE: 305/664-2628 or 305/664-2461.

HUBBA HUBBA. Captain Ken Knudsen quietly poles his flats boat through the shallow water, barely making a ripple. Then he points and his client casts. Five seconds later there's a zing, and the excitement of bringing in a snook, redfish, trout, or tarpon begins. Knudsen has fished Keys waters since he was 12. Now a licensed backcountry guide, he's ranked among the top 10 guides in Florida by national fishing magazines. He offers four-hour sunset trips for tarpon ($300) and two-hour sunset trips for bonefish ($175), as well as half- ($275) and full-day ($375) outings. Prices are for one or two anglers. Tackle and bait are included. MM 79.8, OS, Islamorada, PHONE: 305/664-9281.

SAILORS CHOICE. This company runs a party boat daily plus a night trip on Fridays and Saturdays. The ultramodern 60-ft, 49-passenger boat with air-conditioned cabin leaves from the Holiday Inn docks. MM 99.7, OS, Key Largo, PHONE: 305/451-1802 or 305/451-0041.

Scuba Diving & Snorkeling

AMERICAN DIVING HEADQUARTERS. This place is a good choice for first-time divers. Along with a Water-Tight Guarantee that you'll get your money's worth, the dives start off with a reef ecology and fish identification course so you'll know what you're looking at when you take the plunge. The cost is $60 for a 2-tank dive with tank and weight rental, $85 if you need everything; $97 includes a wet suit, suggested in winter. MM 105.5, BS, Key Largo, PHONE: 305/451-0037.

AMY SLATE'S AMORAY DIVE RESORT. This dive resort makes diving easy. You get out of bed, walk out your room and into a full-service dive shop (NAUI, PADI, YMCA, and British BSAC certified), then onto a boat. They provide accommodations packages and perform underwater weddings. MM 104.2, BS, Key Largo, PHONE: 305/451-3595 or 800/426-6729.

CORAL REEF PARK CO. This outfit offers scuba and snorkeling tours of the park aboard sailing and motorized boats. John Pennekamp Coral Reef State Park, MM 102.5, OS, Key Largo, PHONE: 305/451-6322.

DIVERS CITY, USA. The hours of this dive shop -- daily 8 to 8 -- are a plus for divers who need to purchase equipment or have their own repaired. The shop also offers some of the best prices on equipment in town and runs two-tank, two-location dives for $49.95, tanks and weights included. MM 104, OS, Key Largo, PHONE: 305/451-4554 or 800/649-4659.

FLORIDA KEYS DIVE CENTER. This place organizes dives from John Pennekamp Coral Reef State Park to Alligator Light. The center has two Coast Guard-approved dive boats, offers scuba training, and is one of the few Keys dive centers to offer Nitrox (mixed gas) diving. MM 90.5, OS, Box 391, Tavernier, Islamorada, PHONE: 305/852-4599 or 800/433-8946.

LADY CYANA DIVERS. Since 1980, this PADI five-star training resort has operated dives on deep and shallow wrecks and reefs between Molasses and Alligator reefs. The 40- and 55-ft boats provide everything a diver needs, including full bathrooms. MM 85.9, BS, Box 1157, Islamorada, PHONE: 305/664-8717 or 800/221-8717.

QUIESCENCE DIVING SERVICE, INC. Quiescence sets itself apart in two ways: it limits groups to six to ensure personal attention and offers day, night, and twilight (in summer) dives an hour before sundown, the time when sea creatures are most active. MM 103.5, BS, Key Largo, PHONE: 305/451-2440.

Water Sports

CORAL REEF PARK CO. This outfit fequently renews its fleet of canoes, kayaks, and pontoon and personal glass-bottom boats for scooting around the mangrove trails or the sea. John Pennekamp Coral Reef State Park, MM 102.5, OS, Key Largo, PHONE: 305/451-1621.

FLORIDA BAY OUTFITTERS. You can rent a canoe, a one- or two-person sea kayak, or even camping equipment from Florida Bay Outfitters. Real pros, they match the equipment to the skill level, so even novices feel confident paddling off. Rentals are by the half day or full day. They also sell camping and outdoor accessories, kayaks, and canoes. MM 104, BS, Key Largo, PHONE: 305/451-3018.

FLORIDA KEYS KAYAK AND SAIL. Rent a kayak here, within a 20- to 30-minute paddle of Indian and Lignumvitae keys, two favorite destinations for kayakers. Rates are $10 per hour, $25 per half day. MM 77.5, BS, 77522 Overseas Hwy, Islamorada, PHONE: 305/664-4878.

LIME TREE WATER SPORTS. Captain Elizabeth Jolin runs a well-managed operation. You can sign up for sunset cruises, backcountry fishing trips, and snorkeling and scuba excursions or rent a sailboat, powerboat, kayak, sailboard, or Wave Runner. She also offers PADI diving certification and windsurfing and sailing lessons. MM 68.5, BS, Lime Tree Bay Resort Motel, Long Key, PHONE: 305/664-0052.



The Middle Keys

Stretching from Conch Key to the far side of the Seven Mile Bridge, the Middle Keys contain U.S. 1's most impressive stretch, MM 65-40, bracketed by the Keys' two longest bridges -- Long Key Viaduct and Seven Mile Bridge, both historic landmarks. Activity centers around the town of Marathon, the Keys' third-largest metropolitan area.

Fishing and diving are the main attractions. In both bay and ocean, the deep-water fishing is superb at places like the Marathon West Hump, whose depth ranges from 500 to more than 1,000 ft. Anglers successfully fish from a half-dozen bridges, including Long Key Bridge, the Old Seven Mile Bridge, and both ends of Toms Harbor. There are also many beaches and natural areas to enjoy in the Middle Keys.

DOLPHIN RESEARCH CENTER. The original Flipper movie popularized the notion of dolphins interacting with humans. The film's creator, Milton Santini, also created this research center, now home to a colony of dolphins and sea lions. This not-for-profit organization offers tours and several programs that allow participants to interact with dolphins in the water (Dolphin Encounter), from a submerged platform (Dolphin Splash), and from the water's edge (Tips on Training). Some programs have age or height restrictions and some require 30-day advance reservations. MM 59, BS, Box 522875, Marathon Shores, Grassy Key, PHONE: 305/289-1121 general information; 305/289-0002 interactive program information. COST: Tours $12.50, Tips on Training $35, Dolphin Splash $60, Dolphin Encounter $110. Daily 9-4, walking tours daily 10, 11, 12:30, 2, and 3:30. www.dolphins.org

MUSEUMS OF TROPICAL CRANE POINT. Tucked away from the highway behind a stand of trees, these museums -- part of a 63-acre tract that includes the last-known undisturbed thatch-palm hammock -- are set inn an undeveloped oasis of greenery. The complex includes the Museum of Natural History of the Florida Keys, inside of which are a few dioramas, a shell exhibit, and displays on Keys geology, wildlife, and cultural history. Also here is the Florida Keys Children's Museum, which has iguanas, fish, and a pirate dress-up room. Outside, on the 1-mile indigenous loop trail, you can visit the remnants of a Bahamian village, site of the restored George Adderly House, the oldest surviving example of Conch-style architecture outside Key West. From November to Easter, docent-led tours, included in the price, are available; bring good walking shoes and bug repellent during warm weather months. MM 50.5, BS, 5550 Overseas Hwy., Box 536, Marathon, PHONE: 305/743-9100. COST: $7.50. Mon.-Sat. 9-5, Sun. noon-5; tours conducted when docents available.

SEVEN MILE BRIDGE. This is one of the most-photographed images in the Keys. Actually measuring 6.79 miles long, it bridges the Middle and Lower keys and is believed to be the world's longest segmental bridge, with 39 expansion joints separating its cement sections. Each April, runners gather for the annual Seven Mile Bridge Run.

The expanse running parallel to it is what remains of the Old Seven Mile Bridge, an engineering marvel in its day that's now on the National Register of Historic Places. It rested on a record 546 concrete piers. No cars are allowed on the bridge today, but a 2.2-mile segment is open for biking, walking, and roller blading with a terminus at historic Pigeon Key.

Beach

SOMBRERO BEACH. Pleasant, shaded picnic kiosks overlook a grassy stretch and the Atlantic Ocean here. Separate areas allow swimmers, jet boats, and windsurfers to share the beach. There are lots of facilities, as well as a grassy park with barbecue grills, picnic kiosks, showers, rest rooms, plus a baseball diamond, a large playground, and a volleyball court. The park is accessible for travelers with disabilities and allows leashed pets. Turn left at the traffic light in Marathon and follow signs to the end. MM 50, OS, Sombrero Rd., Marathon, PHONE: 305/289-6077 or 888/227-8136. COST: Free. Daily 7:30-sunset.

Biking

Tooling around on two wheels is a good way to see Marathon. There are paved paths along Aviation Boulevard on the bay side of Marathon Airport, the four-lane section of the Overseas Highway through Marathon, Sadowski Causeway to Key Colony Beach, Sombrero Beach Road to the beach, and the roads on Boot Key (across a bridge on 20th Street, OS). There's also easy cycling on a 1-mile off-road path that connects to the 2 miles of the Old Seven Mile Bridge that go to Pigeon Key.

EQUIPMENT LOCKER SPORT & CYCLE. Cruisers are available here for $10 per day, $50 per week, along with mountain bikes for adults and children. MM 53, BS, Marathon, PHONE: 305/289-1670.

Boating

FISH 'N' FUN. Next to the Boat House Marina, this place lets you get out on the water in 18- to 25-ft boats starting at $95 for a half day, $135-$205 for a full day. You also can pick up bait, tackle, licenses, and snorkel gear. MM 53.5, OS, Marathon, PHONE: 305/743-2275.

Fishing

MARATHON LADY. Morning and afternoon, you can cast for dolphinfish, grouper, and other deep-sea game aboard the 75-ft Marathon Lady and the 65-ft Marathon Lady III, two party boats that depart on half-day ($27 or $25) excursions from the Vaca Cut Bridge, north of Marathon. MM 53.5, OS, at 117th St., Marathon, PHONE: 305/743-5580.

SEA DOG CHARTERS. Captain Jim Purcell, a deep-sea specialist for ESPN's The Outdoorsman, provides one of the best values in fishing in the Keys. His operation, next to the 7 Mile Grill, give personalized half- and full-day offshore, reef and wreck, tarpon, and backcountry fishing trips as well as combination fishing and snorkeling trips on the 32-ft Bad Dog for up to six people. The cost is $59.99 per person for a half day, regardless of whether your group fills the boat, and includes bait, light tackle, licensing, ice, and coolers. If you prefer an all-day private charter, he offers those, too, for $650. MM 47.5, BS, Marathon, PHONE: 305/743-8255.

Golf

KEY COLONY BEACH PAR 3. This nine-hole course near Marathon charges $7.50 for the course, $2 per person for club rental, and $1 for a pull cart. There are no tee times and there's no rush. Play from 7:30 to dusk. A little golf shop meets basic golf needs. They've added two lighted tennis courts, too. MM 53.5, OS, 8th St., Key Colony Beach, Marathon, PHONE: 305/289-1533.

Scuba Diving & Snorkeling

HALL'S DIVING CENTER AND CAREER INSTITUTE. There's more to diving in the Keys than beautiful reefs. So Hall's, next to Faro Blanco Resort, runs two trips a day to Looe Key, a few other reefs, and two wrecks, Thunderbolt, and the Adolphus Busch. MM 48.5, BS, 1994 Overseas Hwy., Marathon, PHONE: 305/743-5929 or 800/331-4255.



The Lower Keys

The Lower Keys comprise just the limestone keys between MM 37 and MM 9. From Bahia Honda Key south, the islands are clustered, becoming smaller and more numerous -- a result of ancient tidal waters flowing between the Florida Straits and the gulf. Here you're likely to see more birds and mangroves than tourists, and more beaches, refuges, and campgrounds than museums, restaurants, and hotels.

The islands are made up of two types of limestone, both more dense than the highly permeable Key Largo limestone of the Upper Keys. As a result, freshwater forms pools rather than percolating, creating watering holes that support Key deer, alligators, fish, snakes, Lower Keys rabbits, raccoons, migratory ducks, Key cotton and silver rice rats, pines, saw palmettos, silver palms, grasses, and ferns. (Many of these animals and plants can be seen in the National Key Deer Refuge on Big Pine Key.)

Nature was generous with her beauty in the Lower Keys. They're home to both Looe Key Reef, arguably the Keys' most beautiful coral reef tract, and Bahia Honda State Park, considered one of the best beaches in the world for it's fine sand dunes, clear warm waters, and panoramic vista of bridges, hammocks, and azure sky and sea.

BAHIA HONDA STATE PARK. This 524-acre sun-soaked, state-owned park sprawls across both sides of the highway, giving it beautiful sandy beaches -- the best in the Keys -- on both the Atlantic Ocean and the Gulf of Mexico. Although swimming, kayaking, fishing, and boating are the main reasons to come, there are many other activities, including walks on the Silver Palm Trail, where you can see rare West Indian plants and several species found nowhere else in the Keys, and ranger-led nature programs. There are rental cabins, a campground, a snack bar, marina, and concessioner for diving, snorkeling, and boating. You can get a panoramic view of the island from what's left of the railroad -- the Bahia Honda Bridge. MM 37, OS, 36850 Overseas Hwy., Bahia Honda Key, PHONE: 305/872-2353. COST: $2 for 1 person, $4 per vehicle for 2-8 people plus 50¢ per person county surcharge; $2 per vehicle an hour before closing. Daily 8-sunset. www.dep.state.fl.us/parks

NATIONAL KEY DEER REFUGE. In the Florida Keys, more than 20 animals and plants are endangered or threatened. Among them is the Key deer, which stands about two feet at the shoulders and is a subspecies of the Virginia white-tailed deer. This 8,354-acre refuge on Big Pine Key was established in 1957, and reports show that under its aegis the deer have made a comeback, more than doubling their numbers to around 800. The best places in the refuge to see the deer are at the end of Key Deer Boulevard (Route 940), off U.S. 1, and on No Name Key, a sparsely populated island just east of Big Pine Key. The Blue Hole, a quarry left over from railroad days, is the largest body of freshwater in the Keys. There are two well-marked trails: the Jack Watson Nature Trail ( mi) and the Fred Mannillo Nature Trail. Headquarters, Big Pine Shopping Center, MM 30.5, BS, Big Pine Key, PHONE: 305/872-2239. COST: Free. Daily sunrise-sunset; headquarters weekdays 8-5.

Biking

A good 10 miles of paved and unpaved roads run from MM 30.3, BS, along Wilder Road, across the bridge to No Name Key, and along Key Deer Boulevard into the National Key Deer Refuge. (You might see some Key deer.) Stay off the trails that lead into wetlands, where fat tires can do damage.

BIG PINE BICYCLE CENTER. Marty Baird, the owner, is an avid rider and enjoys sharing his knowledge of great places to ride. He's also skilled in repairing and selecting the right bike for customers to rent or purchase. His old-fashioned single-speed, fat-tired cruisers for adults rent for $6 per half day, $9 for a full day, and $34 a week, second week $17; bikes for children rent for $5, $7, $26, and $13. Helmets, baskets, and locks are included. MM 30.9, OS, Big Pine Key, PHONE: 305/872-0130.

Fishing

THE GROUCH CHARTERS. The only thing grouchy about Captain Mark André is his original boat's name, derived from his father's nickname. This knowledgeable captain takes up to six passengers on offshore fishing trips ($350 for a half day, $475 for a full day). He also offers packages with accommodations, fishing, snorkeling, and sightseeing for better deals. Summerland Key Cove Marina, MM 24.5, OS, Summerland Key, PHONE: 305/745-1172 or 305/304-0039.

STRIKE ZONE CHARTERS. You can fish with pros year-round in air-conditioned comfort with Strike Zone. Charter rates are $425 for a half day, $550 for a full day. MM 29.6, BS, 29675 Overseas Hwy., Big Pine Key, PHONE: 305/872-9863 or 800/654-9560.

Scuba Diving & Snorkeling

LOOE KEY REEF. In 1744, the HMS Looe, a British warship, ran aground and sank on one of the most beautiful and diverse coral reefs in the Keys. Today, Looe Key Reef owes its name to the ill-fated ship. The 5.3-square-nautical-mile reef, part of the Florida Keys National Marine Sanctuary (MM 27.5, OS, 216 Ann St., Key West, PHONE: 305/292-0311), has stands of elk-horn coral on its eastern margin, purple sea fans, and abundant sponges and sea urchins. On its seaward side, it drops almost vertically 50-90 ft. Snorkelers and divers will find the sanctuary a quiet place to observe reef life, except in July, when the annual Underwater Music Festival pays homage to Looe Key's beauty and promotes reef awareness with six hours of music -- Caribbean, classical, jazz, new age, and, of course, Jimmy Buffett -- broadcast via underwater speakers.

LOOE KEY DIVE CENTER. Rather than the customary morning and afternoon two-tank, two-location trips offered by most dive shops, this operation, the closest dive shop to Looe Key Reef, runs a single three-tank, three-location dive from 10 AM to 3 PM. The maximum depth is 30 ft, so snorkelers and divers go on the same boat. On Saturdays and Wednesdays, the center runs a 3/3 dive on wrecks in the area. It's part of the full-service Looe Key Reef Resort, which, not surprisingly, caters to divers. The dive boat, a 45-ft Corinthian catamaran, is docked outside the hotel, whose guests have free use of tanks, weights, and snorkeling equipment. MM 27.5, OS, Box 509, Ramrod Key, PHONE: 305/872-2215 ext. 2 or 800/942-5397.

STRIKE ZONE CHARTERS. This operator offers dive trips to two sites on Looe Key, resort courses, and various certifications. The outfit uses glass-bottom boats, so nondivers can experience the reef, too. MM 29.6, BS, 29675 Overseas Hwy., Big Pine Key, PHONE: 305/872-9863 or 800/654-9560.

Water Sports

BAHIA HONDA DIVE SHOP. The concessionaire at Bahia Honda State Park manages a 19-slip marina, rents wet suits, snorkel equipment, and corrective masks, and operates twice-a-day offshore-reef snorkel trips ($25) that run almost three hours (with 90 minutes on the reef). Park visitors looking for other fun can rent kayaks ($10 per hour single, $15 double), bicycles, fishing rods, and beach chairs. MM 37, OS, Bahia Honda Key, PHONE: 305/872-3210.