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