It is possible to dive almost anywhere along Thailand’s coast, but the areas around the outflow of Chao Phraya River, including the resorts of Cha Am and Hua Hin southwest west of the river, and Pattaya to the east are not recommended due to their diminished visibility.

Almost everywhere else, dive schools abound, and the waters are warm, clear and brimming with fantastic marine life, including its most famous oceanic celebrity, the Whale Shark.  

The top dive spots in the Gulf of Thailand are Ko Chang in the north and the eastern island chain of Ko Samui, Ko Phangan, Ko Tao and Ko Nang Yuan, with the latter two the best locations. Although diving in the Gulf is possible all year round, the period from September to November is typically a time of reduced visibility and poor weather.

The Andaman Sea islands off the west coast offer Thailand’s very best diving, the most popular destinations in which to be based being Phuket, Krabi, Ko Phi Phi and Ko Lanta, where the local diving is excellent. Diving is possible all year round but is less satisfactory between April and October due to choppier waters and reduced visibility.

Further offshore, the remarkable dives of the Similan and Surin archipelagos regularly feature in lists of the World’s top dive sites and offer stunning underwater experiences. However, it should be noted that a few of the dives can be challenging and are therefore best suited to experienced divers.

Whilst day trips can be arranged from the mainland departing from Khao Lak, by far the best way to visit these islands and enjoy the superb diving is on a liveaboard cruise, leaving from Phuket or Khao Lak. A range of cruises from 4-14 days are available. The islands are managed as a National Park, which is open only from November 16 until May 15 annually, with the best conditions usually occurring in March.

Another great diving opportunity from Phuket is to travel the liveaboard trips to the fabulous Mergui (Meiyk) archepelago of Myanmar, a virtually uninhabited collection of pristine underwater heavens, comprised of over 800 islands.