The Andaman Sea around Thailand & Myanmar offers some of the best diving in Southeast Asia. That is basically all the way down the west coast of Thailand & Myanmar to the border with Malaysia. The area includes Phuket, Koh Phi Phi, Koh Haa, Hin Muang & Hin Daeng in the south. In the north are the world famous Similan & Surin Islands, Richelieu Rock, Koh Bon and Koh Tachai and of course Myanmar. The best time to dive the Similans and Myanmar is during the northeast monsoon from November to April. The islands in Southern Thailand, around Phuket, can be dived year-round. They are among the best diving areas in Thailand, with huge limestone cliffs cascading to beautiful hard and soft coral reefs.