A country of wonders, Thailand offers the traveler many delights, but perhaps none as spectacular as the world below its waves. Tiny Ko Tao and the islet of Ko Nang Yuan lie 24 miles north of Ko Phangan and 36 miles from Ko Samui. Slightly off the beaten track and less well-known than its west coast cousins, the Surin and Similan islands, Ko Tao is regarded as the best dive site in the Gulf of Thailand. The waters around Ko Tao are crystal clear and home to exceptional coral beds and a great variety of reef fish.

Uncrowded beaches and exceptional diving make Ko Tao a paradise for novice and experienced divers alike. In spite of its diminutive size and infamous history as a former penal colony, Ko Tao boasts more than 25 sites, with new areas being discovered all of the time.

Four major sites stand out among the rest in this colorful region, beginning with Ao Leuk, a sandy bay on the south side of Ko Tao. Dramatic rock outcroppings, vividly painted parrotfish, and coral tors give this site the spooky feeling of a surrealist painting on an undersea canvas.

Despite its potentially off-putting name, Shark Island, an elliptical shaped island just off the southeast coast, is one of the most varied dive sites in the area. Explore the island in search of the whale, leopard, and reef sharks for which the site is named. The throngs of dazzling coral fish and stunning soft corals in hues of violet, magenta, and gold, not to mention the resident turtle, make for a memorable underwater tour even if the more infamous citizens stay out of sight.

A school of enormous batfish swims up to greet you as you descend over the breathtaking Chumphon Pinnacle, a gray monolith of four massive rocks that form Ko Tao's most challenging dive site. Starting 110 feet down and soaring to 50 feet below the surface, Chumphon Pinnacle inspires awe. Giant schools of pelagics, including barracuda, mackerel, and tuna, circle the rocks.

Just off the west side of Ko Nang Yuan lies Twins, two rock groupings covered with extraordinary hard corals, peppered with small caves and teeming with more exotic fish. A giant grouper ignores the human intrusion, while white-eyed moray eels and countless puffers keep a keen eye on divers. Before your final ascent be sure to visit the family of orange and black striped clownfish tucked into a solitary anemone.

For the more experienced diver is Green Rock, a maze of swim-throughs, canyons, and caves that will challenge anyone's buoyancy control skills. Toward the deeper end of the site, keep an eye out for white-tip reef sharks, cobia, and whiptail rays as you dip below the thermocline. Beware of the titan triggerfish nests—circular hollows in the sand with very protective occupants!

Practically Speaking

Getting to Ko Samui: The short 70-minute flight from Bangkok is the easiest way to get to Samui. However flights may be full weeks in advance during the high season, December to March and August/September. Fly if you can afford the 2200B fare, or take the overnight train with a ferry package. For the budget traveler there are also a variety of overnight buses that depart from Khao San Road.

Getting to Ko Tao: Ko Tao can be reached by boat from Surat Thani, Ko Samui, or Ko Phangan, though some prefer to first visit Ko Tao from Chumphon and then head south to Phangan and Samui.

The best season to dive in the Gulf of Thailand occurs from January to May and from September to October when peak visibility can reach 100-130 feet.

The range of dive shops on Samui is impressive and quality varies. The Dive Shop (www.thediveshop.net), a small professionally run dive center is a great choice for quality personal attention. Also a five star PADI Instructor Development Center, the Dive Shop offers PADI courses from beginner to professional level starting everyday in a choice of 5 different languages. They also offer daily dive trips on the MV Oasis, a purpose-built, live-aboard dive boat. Certification courses cost between $200-260 for the open water certification, roughly the same for advanced open water certification, including equipment rental.

Scuba certification or individual dives can be arranged through the dive shops near the pier on Ko Tao. Among the larger operations are Master Divers, Big Blue, and Dolphin. Another PADI outlet to the left of the pier is Samui International Diving School.