The South Pacific islands are a dream if you're an active traveler, and especially if you're into diving, snorkeling, swimming, boating, and other watersports. You can also play golf and tennis, or hike into the jungle-clad mountainous interiors of the islands. Kayaking is popular everywhere, and Fiji has river rafting. There's good biking along the many roads skirting colorful lagoons. You can engage in these activities everywhere, although some islands are better than others. Here's a brief rundown of my favorites.

Some travel companies have tours combining several outdoor activities in one trip, especially to Fiji, which has the widest variety of outdoor activities. For example, Colorado-based The World Outdoors (tel. 800/488-8483; www.theworldoutdoors.com) includes mountain biking, hiking, river rafting, sea kayaking, snorkeling, and sailing in its "Fiji Multi-Sport" tour. Travelwizard (tel. 800/330-8820; www.travelwizard.com) sells diving and surfing packages to Fiji and French Polynesia. Likewise, Fiji Adventures tel. 888/418-4461; www.fijiadventures.com) has diving, surfing, river rafting, and windsurfing expeditions to Fiji.

On the Web, Gordon's Guide (www.gordonsguide.com) compiles adventure tours from around the world. It's a good place to search for South Pacific adventure trips. Save time by searching for a specific destination.

Biking

Relatively flat roads circle most of the islands reported on here, making for easy, scenic bike riding. In fact, bicycles are one of my favorite means of getting around. It's simple and inexpensive to rent bikes on all the islands in French Polynesia, the Cook Islands, Samoa, and Tonga. Many hotels and resorts provide bikes for their guests to use.

In Fiji, Active Fiji (www.activefiji.com or www.tuitai.com), formerly known as Tui Tai Adventure Cruises, carries mountain bikes on its eco-cruises.

Diving & Snorkeling

Most of the islands have good to great diving and snorkeling. Almost every lagoon-side resort has a dive operator, and many will let snorkelers go along.

Fiji is on every diver's list of world-class destinations for colorful soft corals. This is especially true in northern Fiji, where nutrient-rich waters bathe the reefs in the Somosomo Strait, between Vanua Levu and Taveuni islands. Here you'll find Rainbow Reef and its Great White Wall. More colorful corals exist off northern Viti Levu and in the Beqa Lagoon, off the island's southern coast. You can watch sharks being fed off Pacific Harbour. Liveaboard dive boats operate in Fiji, too.

French Polynesia is famous for its bountiful sea life, from tropical fish to hammerhead sharks. You'll see plenty of creatures at Moorea, Bora Bora, Huahine, and Raiatea-Tahaa, but the best diving and snorkeling are in the huge lagoons of Rangiroa, Tikehau, Manihi, and Fakarava in the Tuamotu Islands.

The shallow lagoons in the Cook Islands and the Samoas are fine for snorkeling, but most diving is in open water outside the reef, where you'll see ample sea life swimming in caves and canyons. Tonga offers a mix, with lagoon diving off Tongatapu and Vava'u and open-water dives off the island of Eu'a.

Most resorts offer dive packages to their guests, and the American-based PADI Travel Network (tel. 800/729-7234; www.padi.com) puts together packages for divers of all levels.

Deep-Sea Fishing

Charter boats in every country will take you in search of marlin, swordfish, tuna, mahimahi, and other game fish. For example, a lucky Australian angler recently snagged a record-breaking 328.8kg (725 lb.) black marlin off Vava'u in Tonga, which to my mind is the best place to go deep-sea fishing in the islands.

In French Polynesia you can cast your line while living in relative luxury in the Tuamotu Archipelago aboard Haumana Cruises (www.tahiti-haumana-cruises.com), which uses a 17-cabin yacht.

Golf & Tennis

Most islands have at least one golf course, and some hotels and resorts have tennis courts, but generally this is not the place for a golf and tennis vacation.

Notable exceptions are in Fiji, where Denarau Golf & Racquet Club is a modern complex with an 18-hole resort course and 10 tennis courts. Fiji is home to the region's most picturesque course, The Pearl Championship Golf Course & Country at Pacific Harbour.

French Polynesia has an 18-hole set of links on Moorea to complement the venerable Olivier Breaud International Golf Course, on the south coast of Tahiti.

The Cook Islands have two 9-hole courses, one on Rarotonga and one on Aitutaki. Both are famous for their antenna guy-wire obstacles, which are in play. Samoa has three courses, the newest wrapping around Aggie Grey's Lagoon, Beach Resort & Spa. Tonga has one flat course.

Hiking

These aren't the Rocky Mountains, nor are there blazed trails out here, but hiking in the islands is a lot of fun.

In Fiji you can trek into the mountains and stop at -- or stay in -- native Fijian villages. Adventures Fiji, an arm of Fiji's Rosie the Travel Service (www.rosiefiji.com), has guided hikes ranging from 1 to 10 days into the mountains of Viti Levu, with meals and accommodations provided by Fijian villagers. On Taveuni island, you can hike a spectacular Lavena Coastal Walk to a waterfall or up to Lake Tagimaucia, in a crater at an altitude of more than 800m (2,700 ft.). It's home to the rare tagimaucia flower.

Tahiti and Moorea have several trails into the highlands, some of which run along spectacular ridges. You'll need a guide for the best hikes, but you can easily hire them on both islands.

Rarotonga in the Cook Islands is famous for its Cross-Island Trek, which runs across the mountains from coast-to-coast.

Samoa has several excellent walks, including a breathtaking coastal trail in O le Pup-Pue National Park and a strenuous trek to the mountaintop Lake Lanoto'o. Likewise, you'll find stunning scenery along the trails in the National Park of American Samoa.

Horseback Riding

Although I prefer sipping a cold drink, a great way to experience a South Pacific sunset is from the back of a horse while riding along a beach. You can do just that in Fiji, on Moorea and Huahine in French Polynesia, and on Rarotonga in the Cook Islands.

The ranches on Moorea and Huahine have daytime rides into the mountains.

Kayaking

All but a few beachfront resorts have canoes, kayaks, small sailboats, sailboards, and other toys for their guests' amusement. As most of these properties sit beside lagoons, using these craft is not only fun, it's relatively safe. They are most fun where you can paddle or sail across the lagoon to uninhabited islets out on the reef, such as on Moorea's northwest coast and off Muri Beach on Rarotonga in the Cook Islands.

Sea kayaking is popular throughout the islands, especially among Fiji's small islands. Tamarillo Tropical Expeditions (tel. 877/682-5433 in the U.S., 4/2399-855 in New Zealand; www.tamarillo.co.nz) has guided 5- to 9-day kayak trips along the shore of Fiji's Kadavu island.

In Samoa, you can take kayak tours of a mangrove estuary and the small islands of Manono and Apolima.

In Tonga, Friendly Islands Kayak Company (www.fikco.com) leads trips through Vava'u's multitude of islets.

River Rafting

Only Fiji has rivers long enough and swift enough for white-water rafting. The best is the Navua River on Viti Levu, which starts in the mountainous interior and flows swiftly down to a flat delta on the island's south coast. Local companies offer trips using traditional bilibilis (bamboo rafts) on the lower, slow-flowing section of the river. The American-based Rivers Fiji (tel. 800/346-6277; www.riversfiji.com) uses inflatable rafts for white-water trips up in the highlands.

Sailing

The region's reef-strewn waters make charter-boat sailing a precarious undertaking. The exceptions are the Leeward Islands in French Polynesia and Vava'u in Tonga, where you can rent sailboats with or without skippers. The Moorings (tel. 800/535-7289; www.moorings.com), one of the world's leading yacht charter companies, has operations at both locations.

Surfing

The islands have some world-famous surfing spots such as Frigates Passage in Fiji and Teahupoo on Tahiti. All the best are reef breaks; that is, the surf crashes out on coral reefs instead of on sandy beaches. These are no places for beginners, as you could suffer serious injury by landing on a razor-sharp coral reef. (Or as one of my island friends puts it, "You'll become hamburger in a hurry.")

The surf pounds directly on beaches on Tahiti, where you can learn to surf with Ecole de Surf Tura'i Mataare (Tahiti Surf School) (tel. 41.91.37; www.tahitisurfschool.info).

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.