Thailand

Best overall months to dive: Feb–Apr

Thailand has two dive coasts on offset monsoon clocks. Phuket is the Andaman Sea's main day-boat hub, with Racha Yai training dives and stronger-current Racha Noi sites. Farther offshore, the Similan and Surin Islands, Hin Daeng and Hin Muang, Phi Phi and Koh Lanta, and Koh Lipe each have their own access limits and monsoon exposure. Several Andaman national parks close through the southwest monsoon. The Gulf side splits in two: Koh Tao runs year-round and handles a high volume of scuba training, while Koh Chang is strongest from November to April around the HTMS Chang wreck. Because the coasts are offset, at least one region is normally operating, but conditions are not interchangeable.

Dive regions