Costa Rica's Cocos Island, 300 nautical miles from the Pacific Coast, is world-famous for close encounters with sharks, giant rays and dolphins. Setting off from live-aboard ships, divers can observe swirling schools of hammerheads. The pristine island was the inspiration for Michael Crichton's Isla Nublar in "Jurassic Park" and is also home to some 200 spectacular waterfalls, many of which drop right into the sea. Jacques Cousteau visited the island several times and claimed it was "the most beautiful island in the world." Don't pass up a visit to Costa Rica's lush Osa Peninsula or Drake Bay before or after your dives.

For more information: Cocos Island

Before it was a tourist destination, Coiba was a penal colony for most of the 20th century. Access, therefore, was tightly restricted, which means that some 80 percent of the island's natural resources have avoided the logging, over-fishing and development that have marred parts of the mainland. Coiba is surrounded by one of the largest coral reefs on the Pacific coast of the Americas, and the warm Indo-Pacific current brings with it corals and rare tropical marine life. The island is loosely connected to Cocos Island and the Galapagos by an underwater mountain range.

For more information: Coiba Island

Two hundred miles off the northeastern coast of Brazil, Fernando de Noronha archipelago is a strictly controlled marine park that has never been commercially fished. Therefore, it's a sanctuary for open sea marine life, which includes sea turtles, sharks and the largest residential school of dolphins on earth. Not only do the 600-plus spinner dolphins breed and live there, but they can be seen cavorting in the bay dozens at a time. The archipelago also offers surfing, kayaking, hiking, bird-watching, quite a few excellent hotels, and some of the top beaches in Brazil.

For more information: Fernando de Noronha

The Lakshadweep Islands continue to emerge as a destination for relaxation, scenery, solitude and, of course, diving -- that is, for the well-heeled adventure travelers in the know. These nearly 40 islands and islets are grouped into twelve atolls -- and sparsely populated. Many of the islands, in fact, remain closed to visitors. Scuba diving centers operate out of Kadmat and Kavaratti islands, and provide access to dive sites with impossibly good visibility. Kadmat is also the base for a number of other watersports such as kayaking, wind surfing and water skiing. Back on the mainland, the state of Kerala offers the chance to visit tropical India at its best.

For more information: Lakshadweep Islands

The Maldives may be the ultimate winter scuba escape. The water is warm throughout the year, visibility is excellent, the accommodations are flawless and the food is both fresh and imaginative. What's more, the beaches are immaculate and there are many opportunities to see large and impressive sea life. Aside from the capital Male, there are no hotels in the Maldives, only all-inclusive resorts. Dive resorts -- common, but not the only option -- are found in the more far-flung parts of the archipelago, as the outer atolls tend to have better access to larger marine species.

For more information: Maldives

It just so happens that some of the northern hemisphere's colder months -- January through April -- are the best time for diving in Abrolhos. Off the coast of Bahia, Brazil's culturally and historically rich state that glows with its legacy of African heritage, Abrolhos is one of the best places in the Americas to see humpback whales. Weighing up to 30 tons, the whales escape the Antarctic cold to swim to Abrolhos to mate and give birth. The surrounding reefs are known for their unusual pinnacles and coral formations that make for outstanding diving.

For more information: Abrolhos

The Similan Islands lie off the coast of Phang Nga Province in southern Thailand. According to marine conservationist and diver Petchrung "Aey" Sukpong, "Similan coral reefs host a variety of reef fishes and invertebrates; more than 240 stony coral species and more than 600 reef fish species have been identified." Aey works with the Green Fins Project to protect and conserve these reefs through sustainable diving practices. The underwater topography is also known for its prominent pinnacles and other rock formations. Access to the Similan Islands is easiest from the resort beach of Khao Lak, a short distance from Phuket.

For more information: Similan Islands

Part of the island-nation of Grenada, the smaller island of Carriacou is both an excellent dive destination and throwback to the Caribbean of yesteryear. With a small dock that does not accommodate cruise ships, the island welcomes visitors but is not defined by international tourism. Traditional fishing, boat building and festivals are still commonplace and bars, cafes and beaches cater equally to locals and foreigners. As Werner "Max" Nagel, owner of Carriacou Silver Diving, the island's original dive shop, points out, "Carriacou's world-class dive site is called the Sister-Rocks and features eagle-rays, stingrays, giant green moray eels and family-clans of lobsters and black coral, just to name a few highlights."

For more information: The Grenadines

Part of the island-nation of Grenada, the smaller island of Carriacou is both an excellent dive destination and throwback to the Caribbean of yesteryear. With a small dock that does not accommodate cruise ships, the island welcomes visitors but is not defined by international tourism. Traditional fishing, boat building and festivals are still commonplace and bars, cafes and beaches cater equally to locals and foreigners. As Werner "Max" Nagel, owner of Carriacou Silver Diving, the island's original dive shop, points out, "Carriacou's world-class dive site is called the Sister-Rocks and features eagle-rays, stingrays, giant green moray eels and family-clans of lobsters and black coral, just to name a few highlights."

For more information: The Grenadines

Los Roques islands are 50 islands, cays and islets scattered across the shallow blue and green waters north of Caracas. The islands attract many kitesurfers, sportfisherman and sun worshippers, but are also known as a world-class dive spot. Most visitors stay on the island of Gran Roque (the Big Rock) that houses a number of delightful posadas and small restaurants, while others anchor their yachts in the protected waters offshore. You can dive to a massive submerged pinnacle in the open sea or drift along reefs in the morning and spend the afternoon eating local lobster on one of the sandy islets.

For more information: Los Roques

assembled an expert panel of underwater adventurers to identify the 10 best scuba spots in the world.

The nature of the dive site's waters are what the panel took into consideration when choosing the top 10. While accommodations are important, for the serious diver, where you spend your time on land is hardly a factor in picking a site. There are certain base conditions that will guarantee a great dive site. “Vertical walls in deep, pollution-free water give divers face-to-face encounters with pelagic species … upwelling off points adds a rich food supply so these are where you will find [thriving marine life],” explains Jack Jackson, underwater photographer and author of dozens of books on diving.

© Gunther Deichmann/Courtesy of Sam's Tours

Blue Corner, Palau, teems with all manner of sea life—from turtles to barracudas and sharks. There are WWII wrecks, too. The current is fairly strong here, and most divers use a reef hook so you can "just kinda hang out and watch the action in front of you," says Tom Morrisey. "If you're lucky you'll see lots of sharks feeding naturally right in front of you… a lot people call it the best dive in the world." The best time to dive Palau is from October to early June.

For more information: Micronesia

Blue Hole, Lighthouse Reef, Belize

© Tony Roth

With very little marine life, the Blue Hole is more a geological trip than a visit to the zoo. An unbelievable sight from the air, the almost perfectly circular Blue Hole was created by what was a dry cave system in the Ice Age. At 110 feet below sea level, the caves have stalactite formations where reef and hammerhead sharks lurk in the shadows. The water stands perfectly still and one can stare up through the passage to the sky above. "It's so distinctive a feature. It's very striking," says Morrisey. May and June are the best months to spot sharks circling the hole.

For more information: Belize

Coron Island, Philippines

© Miguel Angelo Silva

Coron Island is a wreck diver's playground, with Japanese WWII ship wrecks scattering the area. "The future for divers here is immense," says Jackson. Swim from bow to stern exploring the corals growing from the rotted wood, and the colorful schools of fish that have made their homes in the crow's nest. For the superstitious who would rather steer clear of sunken vessels, investigate the shallow coral gardens and underwater caverns nearby. Philippines' diving is great for all levels, with fabulous snorkeling for the less adventurous. April and May have the best dive weather.

For more information: Philippines

Bonaire, Dutch Caribbean

© Bonaire Tourism

Despite its stunning beaches, Bonaire, 50 miles off the coast of Venezuela, is best known for spectacular shore diving, and is ranked #2 on the PADI network of top 10 travel destinations. "You can basically gear up and walk on the beach into the water," explains Lucey. The beauty of Bonaire dives is the comfort and accessibility found with developed dive sites. Bonaire offers good diving year-round, and is one of the only dive locations that you can dive 24 hours a day.

For more information: Bonaire

Southern Red Sea, Sudan

© Martin Strmiska

For some of the most untouched scuba diving, head to the mystifying waters of the Red Sea. "The political problems all over Sudan make it difficult to get to, but also protects the diving from crowds," says Jackson. Sudan's diving requires live-aboard boats with little else to do on the boat. Spend your free time day dreaming about likely sightings of angelfish, butterfly fish, stingrays, manta rays, wrasse and other creatures flitting amongst the reefs. At 85 feet you will likely encounter Tip Reef, Silvertip, Silky and Scalloped Hammerhead sharks. Be sure to book from May to September when the weather is best.

For more information: Tony Backhurst Scuba

Cocos Island, Costa Rica

© Cousteau Society

While Cocos Island, located 300 miles off the coast of Costa Rica, offers live-aboard diving only, you'll find the animals you come in contact with are worth the boat bobbing. Surround yourself with hundreds of Hammerhead sharks, swim with dolphins, tuna, the gigantic marble rays, even whale sharks. "This is a must do dive destination," says Christopher. Cocos Island is ranked as the #6 best dive site by the PADI network. Plan your trip to the island from May to October for the best conditions.

For more information: Cocos Island

Coral Sea, Great Barrier Reef, Australia

© Tourism Queensland

The Old Faithful for divers, the Great Barrier Reef has aged gracefully as an underwater destination. "Suitable for all levels of diver, the Great Barrier Reef can be dived all year round," says Jackson. PADI network has ranked the Reef as #10 of their 10 best diving spots. Calmest in October, Jackson finds the Coral Sea to be the best place for diving in the Reef. Sea snakes and sharks are common sightings, and there the mythical visibility of close to 200 feet is what keeps bringing divers back.

For more information: Great Barrier Reef

Bali, Indonesia

© Martin Strmiska

Bali is the easiest part of Indonesia to travel, and its reef diving is a world-class experience. Located ideally between the Indian and Pacific oceans, a faultless current allows leisurely exploration of the diverse landscapes of pinnacles, coral gardens and black volcanic sands, perfect for the underwater photographer. These are also supreme waters for those more interested in the creatures of the sea. "These nutrient-rich waters support a cornucopia of bio-diversity," says Christopher. "Rare, unusual species can also be found by the lucky diver." The best time for diving Bali is September and October.

For more information: Aquamarine Diving Bali

Dinah's Beach and Observation Point, Papua New Guinea

© Jurgen Freund

Dinah's Beach is an ideal spot for "muck" diving. With a lower visibility, divers are forced to get very close to what they are looking at, giving a new perspective of underwater surroundings. "This type of diving results in finding unusual creatures," explains Jackson. Jackson mentions sightings of Harlequin, Ghost Pipefish, Spiny Devilfish, Cockatoo Wasp fish and Merlet's Scorpion fish. While most dive sites in Papua New Guinea are live-aboard, there is the opportunity to venture onto land for hikes or exposure to the different native inhabitants. The weather is best for diving in Papua New Guinea from mid-October through June.

For more information: Ocean First Divers Papua New Guinea