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

The six-gill shark is one of the largest and most mysterious sharks in the ocean. They've been around since prehistoric times and can grow up to 20 feet in length. And because they live in the darkest depths of tropical oceans, few humans have encountered them. Shark Diver is the only company in the world to use research-grade mini-subs to bring tourists down 2000 feet into the Cayman Trench, where they'll see some of the planet's rarest marine life and come face to face with the steely eyes of this giant monster of the deep. It's lured to the sub's window by a tasty pig's head.

For more information: Deep Sub Shark Adventures

Near…Far…Wherever you are, the lure of the world's most famous shipwreck continues to entice more than just the imaginations of James Cameron's devotees. A select few expeditions depart the Canadian mainland each summer, setting out over the choppy North Atlantic aboard sturdy research vessels outfitted with Russian MIR submersibles, which dive the two and a half miles down to reach the "unsinkable" ship's remains. Only a few dozen people get to see the Titanic each year, which means your bragging rights at the bar are almost assured.

For more information: Titanic Dive. St. John's

For those who love choosing their dinner from the lobster tank, the swimming buffet just beyond the clear acrylic at the Ithaa Undersea Restaurant will leave you drooling. This unique eatery sits 16 feet below the tropical water's surface, right next to a vibrant coral garden. Though not much larger than a subway car, the unobstructed dome allows views of an entire ecosystem to accompany the cuisine, which is a fusion of Western and local flavors, largely based around seafood. And while you can't just point to your right and say "I'll have that one," a generous tip to the busboy might induce him to fetch a spear gun.

For more information: Ithaa Undersea Restaurant

Slated to open sometime in 2009 or 2010, the Poseidon will likely be the world's first underwater resort, where guests will descend via elevator to individual suites on the ocean floor. On-site activities will include mini-sub pilot lessons, submarine excursions into the ocean's depths, scuba diving and good old-fashioned beach bumming. The resort's developer even plans to build a luxury guest cabin that will be perched on a wall 1000 feet below the surface, accessed by a private sub. Just be sure not to forget your keys at the restaurant. Future resorts are planned for sites in the Mediterranean, Caribbean, Red Sea and Indian Ocean.

For more information: Poseidon Undersea Resort

The pioneer in underwater lodging is more motel than hotel, but it's also the only undersea dwelling in the United States. Guests must be certified scuba divers to reach the lodge, but once down they can relax in the aquatic-themed interior (think: sea scenes printed on linens and pillows shaped like fish). The lodge's "Mer-Chef" dives down to cook meals each night, and can even cater weddings, should you wish to pledge your everlasting love in every conceivable environment.

For more information: Jules' Undersea Lodge

Though construction hasn't yet begun, financing is well underway for these aquatic super-complexes, which very much resemble space stations from sci-fi novels. Each will be anchored close to a land-based megatower, which will connect to the floating cities by way of tunnels. These won't just be resorts but "Oceanic Settlements", where people will live, play and, presumably, fish. Though Dubai and Qingdao are the first slated to open, there are talks of additional locations in London, Monaco, Munich and New York—all cities where the price of land could drive people to the apartments Hydropolis plans to sell out at sea.

For more information: Crescent Hydropolis Resorts

As if a "Unite Me-Crystal Ritual" treatment, complete with local virgin coconut oil wood massage, wasn't relaxing enough, this new resort has taken the spa experience and plunged it underwater, with two double treatment rooms suspended right amidst the corals. Peering out through the windows, as trained hands knead away whatever possible stress remains in your body, be sure not to hum "Octopus' Garden" too loud. You might scare the fish.

For more information: Huvafen Fushi Resort

Why pay guides and tour companies to take you on submarines, when you can just pony up and buy your own? The SEAmagine models are the exact same types of deep-sea submersibles used to explore shipwrecks and research marine life, and can descend hundreds of feet below the surface. You'll probably have to buy an appropriate adventure-class yacht to lower the sub into place, but what's another multimillion dollar vessel on the credit card?

For more information: SEAmagine Submersibles

U.S. Submarines has done for personal subs what Gulfstream did for airplanes—married the styling and comfort of a luxury yacht with the versatility and technology of military-grade equipment. The company's vessels range from two- and three-passenger personal submersible pleasure craft to sunken pleasure palaces that can stay under for weeks at a time with staterooms, kitchens, scuba escape hatches and detachable mini-subs. It's the ultimate in discretion and big-toy luxury, and when you buy one, you purchase the rare opportunity to yell "Dive! Dive! Schnell!" at your bewildered crew. The only downside is that they come with neither periscopes nor torpedoes.

For more information: U.S. Submarines

The biggest long shot in the undersea resort game is the aptly named Undersea Resort. Backed by a Florida plastics company that intends to build floating (not moving) cruise ships with underwater viewing areas, these will be permanently moored offshore or in harbors. They promise all the amenities of cruising—theaters, spas, water slides—plus views of sea life. So far, they've received no orders—proof positive that underwater resorts are still quite speculative.

For more information: Undersea Resort

sources: cyber diver