Active Pursuits

If it's aquatic, St. Maarten/St. Martin offers it: from sailing to scuba diving, big game fishing to boogie boarding. It almost seems the island has more marinas per square mile than anywhere else on earth (one even changed its name to Dock Maarten, neatly combining two local economic mainstays -- boating and shopping). Land-based excursions are less popular, though hiking and mountain biking can be rewarding.

Boating

Sea dogs will happily bark (or bite) at Lagoon Sailboat Rental in Simpson Bay Lagoon (tel. 599/557-0714; www.lagoonsailboatrental.com). You can explore the lagoon and surrounding waters in state-of-the-art 6m (20-ft.) Sunfasts for $150 for a full day ($110 for a half-day). The congenial Cary and company also give a thorough 10-hour course for $200 (minimum two people, maximum three) that can be broken up however you like.

Come Sail Away -- Ever wonder what racing a swift state-of-the-art yacht is like? The St. Maarten 12-Metre Challenge in Philipsburg at Bobby's Marina (tel. 599/542-0045; www.12metrechallenge.com) gives nautical nuts a chance to crew on one of five famed America's Cup yachts specially designed for the 1987 competition off Fremantle, Australia. The marquee boats include Dennis Conner's champion Stars & Stripes, True North, and Canada II. Each boat takes nine to 18 competitors (12 and up) for a thrilling 3-hour race ($80-$100 per person). Previous sailing experience isn't required: The captains and mates brief their swabs-for-a-day on the basics, from grinding a winch to tacking. Or you can just drink in the experience along with rum punches, letting everyone else worry about even keels.

Deep-Sea Fishing

The island hosts several highly regarded competitions, including May's Marlin Cup and June's Billfish Tournament, that lure an impressive international roster of entrants. The waters teem with tuna, wahoo, snapper, grouper, jack, pompano, yellowtail, marlin, and other big game fish. The crew from Lee's Roadside Grill on Welfare Road 84, Simpson Bay (tel. 599/544-4233; www.leesfish.com), knows where to catch the big boys, since they supply their own wildly popular seafood haunt. Its 9.3m (31-ft.) Bertram, Baby Blues, is available for a minimum of four people (maximum six). Drinks are included in the half-day trip ($200) and lunch and drinks are included in the 3/4- and full-day excursions ($250 and $300, respectively). And yes, they'll cook your trophy up at the restaurant.

On the French side, Big Sailfish Too (tel. 690/27-40-90) at Anse Marcel will take four to eight anglers aboard a 32-ft. Hatteras. The crew is knowledgeable, the tackle high quality, and the rum punches strong. Drinks are included for half-day charters ($600; maximum 5 people); add lunch to the full-day trip ($1,100; maximum 5 people).

Golf

The Towers at Mullet Bay (tel. 599/545-3069; www.towersatmulletbay.com), a timeshare condominium complex on the Dutch side, is where you'll find the island's only golf course. It's a slightly battered, slightly dusty 18-hole Joseph Lee-designed course, whose fate has hung in the balance, based on some ongoing court battles, for years. Mullet Pond and Simpson Bay Lagoon provide both beauty and hazards. Greens fees are $60 for 9 holes or $88 for 18 holes, for players who opt to walk instead of ride. Renting a two-person electric cart will cost an additional $8 to $18 depending on how many holes you play. Club rentals cost $21 for 9 holes or $26 for 18 holes.

Hiking & Mountain Biking

Despite its small size, the island offers terrain ranging from limestone plateaus to a central volcanic ridge topped by 445m (1,482-ft.) Pic du Paradis, and ecosystems from semi-desert to tropical rainforest. Birders will sight coots, black-necked stilts, and ospreys nesting amid the swamps and cliffs.

Adrenaline junkies and eco-buffs will feel at home at TriSport headquarters on 14B Airport Rd. in Simpson Bay (tel. 599/545-4384; www.trisportsxm.com). Bikers can rent Trek mountain bikes and hybrids ($17 half-day, $24 full day, $110 per week). TriSports also ventures into the open water with snorkeling/kayaking tours around Anse Guichard's hulking Henry Moore-ish boulders and Caye Verte. The 2 1/2-hour Simpson Bay Lagoon tour ($49) includes instruction and a stop at deserted Grand Îlet, whose mangrove system houses unusual critters from sea cucumbers to upside-down jellies. You can rent kayaks for $15 per hour; a double kayak costs $19/hr.

Horseback Riding

In its new location in Seaside Nature Park, Lucky Stables (tel. 599/544-5255) offers a romantic Moonlight Champagne ride ($70 per person) including a marshmallow roast or a sunset jaunt (from $45). Guides explain local folklore, fauna, and flora along the picturesque route through the closest thing to wilderness on the Dutch side. In its new location, Lucky Stables will also be offering carriage rides, snorkeling tours, and a bar on the beach. The highlight is a ride into secluded, stony, unspoiled Cay Bay (aka Cape Bay) as Saba, Statia, St. Kitts, and Nevis drift on the horizon. Suddenly the horses wade into the warm water; your saddle feels like a flotation device as they swim with surprising grace. There's time to go shelling and snorkel in the offshore reef (without your ride, of course). It's also an excellent vantage point for whale-watching in spring and waterfowl sightings year-round. Private lessons are $35 for half-hour. Barring heavy traffic, the stables are 10 minutes from the airport and 15 minutes from Philipsburg.

Its eco-sensitive counterpart on the French side is Bayside Riding Club, rue de la Galion, Coconut Grove (tel. 590/87-36-64; www.baysideridingclub.com). Prices start at $70 per person for 1-hour group beach rides. Group sunset beach rides are $80 per person. Here too, the highlight is swimming astride your mount in the water. Children can take pony rides for $35 per half-hour.

Scuba Diving

Scuba diving is excellent around St. Martin, with reef, wreck, night, cave, and drift diving; the depth of dives is 6 to 21m (20-69 ft.). Off the northeastern coast, dive sites include Îlet Pinel and Creole Rock, for shallow diving; Green Cay, a barrier reef; and Tintamarre, for sheltered coves and geologic faults. To the north, Anse Marcel and neighboring Anguilla are good choices. St. Maarten's crystal-clear bays and countless coves make for good scuba diving as well as snorkeling. Underwater visibility runs from 23 to 38m (75-125 ft.). The biggest attraction for divers is the 1770 British man-of-war, HMS Proselyte, which came to a watery grave on a reef 2km (1 1/4 miles) off Philipsburg in 1801. Other excellent sites include Tugboat Annie, Frenchman's Reef, Lucy's Barge, Pelican Rock, the double pinnacles of One Step Beyond, Moonhole (a large crater with caves and walls of sponges), and the intact fishing vessel Fu Cheng 36m (120 ft.) down.

Memorable sightings amid virtual mountain ranges of coral with crevices, ledges, and drops galore include schools of vibrantly colored fish from grunts to queen angels, sea fans beckoning like come-hither courtesans, stingrays, mantas, moray eels, barracuda, tarpon, banded coral shrimp, Caribbean spiny lobsters, endangered turtles (green, leatherback, hawksbill, loggerhead), and reef and nurse sharks. Most of the big resorts have facilities for scuba diving and can provide information about underwater tours, photography, and night diving.

Scuba Fun Dive Center has offices at Marina Port Lonvilliers, Anse Marcel (tel. 590/87-36-13; www.scubafun.com), and Dock Maarten Marina, Great Bay, Pointe Blanche (tel. 599/542-3966). Morning and afternoon dives in deep and shallow water, wreck dives, and reef dives cost $45 per dive (certified divers only). A resort course for first-time divers with reasonable swimming skills costs $75 and includes 45 minutes of instruction in a swimming pool and a one-tank shallow dive above a coral reef. Full PADI certification costs $350, an experience that requires 5 days and includes classroom training, sessions with a scuba tank within the safety of a swimming pool, and three open-water dives. Snorkeling trips cost $30 for a half-day, plus $10 for equipment rental.

Dive Safaris, at two locations -- at Bobby's Marina, Philipsburg (tel. 599/542-9001), and Simpson Bay (tel. 599/545-2401; www.divestmaarten.com) -- offers competitive rates and a full range of PADI certification courses, including specialty instruction in marine habitats, photography, and wreck diving. Those wanting to get up close and personal with sharks can don chain-mail-like armor to feed the sharks in their "Shark Awareness Dives."

The larger-than-life owner of Ocean Explorers at Kim Sha Beach (tel. 599/544-5252; www.stmaartendiving.com), LeRoy French, is still diving more than a half-century after he caught the bug (using some of Cousteau's first Aqua Lungs). Starry students in his 40-plus-year career have included Jackson Browne, Matthew McConaughey, and Sandra Bullock. He's been profiled by Sports Illustrated, and even the Cousteau team might envy his vivid videos. The personalized touch -- he takes a maximum of six divers -- costs a bit more ($49-$55 single dive, $100 double; $360 full certification) and means reservations are essential.

Snorkeling

Calm waters ringing shallow reefs and tiny coves make the island a snorkeler's heaven. The waters off northeastern French St. Martin have been classified as a regional underwater nature reserve, Réserve Sous-Marine Régionale, which protects the area around Flat Island (also known as Tintamarre), Îlet Pinel, Green Key, and Petite Clef. Equipment can be rented at almost any hotel, and most beaches have watersports kiosks. The waters surrounding the entire Dutch side to a depth of 60m (200 ft.; with designated fishing, scuba, and shipping zones) are protected as the St. Maarten Marine Park, which also inaugurated an Artificial Reef program, utilizing special balls to imitate the appearance and function of natural coral reefs. The island's top snorkeling beaches are Mullet Bay, Cay Bay, Little Bay, Dawn Beach, Plum Bay, and Baie Rouge.

One of St. Martin's best sources for snorkeling and other beach diversions is Carib Watersports (tel. 590/87-51-87), a clothing store, art gallery, and watersports kiosk on the beachfront of the Grand Case Beach Club. Its French and U.S. staff provides information on island activities and rents kayaks and paddleboats for $20 an hour and snorkeling equipment for $10 a day. The main allure, however, are the guided snorkeling trips to St. Martin's teeming offshore reefs, including Creole Rock, an offshore clump of reef-ringed boulders rich in underwater fauna. The 2-hour trips depart daily at 10am, noon, and 2pm; cost is $30 including equipment. Reservations are recommended.

Tennis

You can try the courts at most of the large resorts, but you must call first for a reservation. Preference, of course, is given to hotel guests.

On the Dutch side, there are four courts at the Maho Beach Hotel, Maho Bay (tel. 599/545-2115). Port de Plaisance, Cole Bay (tel. 599/544-5222) has seven courts. The Pelican, Simpson Bay (tel. 599/544-2503) has four courts, and the Divi Little Bay Beach Resort, Little Bay Road (tel. 599/542-2333), has one court, but they are for guest play only. On the French side, Esmeralda Resort, Orient Bay (tel. 590/87-36-36) has two courts.

Water-Skiing & Parasailing

Most of French St. Martin's large beachfront hotels maintain facilities for water-skiing and parasailing, often from kiosks that operate on the beach.

Club Caraïbes at the Hôtel Mercure Simson Beach in Nettle Bay (tel. 690/33-30-01; www.skicaraibes.net) provides wakeboard and jet ski rentals, as well as water-skiing instruction with Laurent Guy and Brigitte Lethem (the 2004 U.S. Master Champion). You can learn slalom or tricks for 35€ ($53) per set; 5-day intensive water-skiing and wakeboard courses cost 320€ to 660€ ($480-$990).

Windsurfing & Kiteboarding

Most windsurfers gravitate to the eastern part of the island, most notably Coconut Grove/Le Galion Beach, Orient Beach, and to a lesser extent, Dawn Beach, all in French St. Martin. The top outfitter here, Tropical Wave, Le Galion Beach, Baie de l'Embouchure (tel. 590/87-37-25; www.sxm-orientbeach.com/chezpat), capitalizes on the near-ideal combination of wind and calm waters. Pat rents Mistrals for 20€ ($30) an hour, with instruction offered at 30€ ($45) an hour, and 45€ ($68) for a 2-hour beginner course. They also rent snorkeling gear, pedal boats, and kayaks (tours can be arranged).

Wind-Adventures (formerly Club Nathalie Simon) on Orient Beach (tel. 590/29-41-57; www.wind-adventures.com) is one of the Caribbean's premier windsurfing schools. Lessons cost 40€ ($60) per hour, 55€ ($83) for 1 1/2 hours. Kite trips for the experienced to Green Cay start at 95€ ($143). CNS also rents windsurfers and Hobie Cats from 35€ ($53) per hour, and offers both safaris and instruction (with excellent multilesson discounts). Equipment is state-of-the-art. Wind Adventures also offers kitesurfing, kayaks, island excursions, eco-tours, and a number of kids' activities.