Activities · Country Guide
Two seas, two seasons: build your Thailand trip around the coast that is in form
Updated Mar 4, 2026 • 10 sources
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Thailand gives you two completely different scuba playgrounds in one country. The Andaman Sea side (base on Phuket, Krabi, or Khao Lak) is about offshore reefs and seasonal marine parks, with the Similan and Surin island groups delivering wide-angle boulders, walls, and higher chances of pelagics. The Gulf of Thailand side (especially Koh Tao and Chumphon) is course-central: warm water, short boat rides, and an easy progression from beginner reefs to current-swept pinnacles.
If you are flexible with dates, you can often choose the coast that is calmer that month, rather than forcing a monsoon window.
Khao Lak and the Similan-Surin offshore circuit
Base on Khao Lak for the Similan Islands when you want Thailand's most iconic Andaman diving: boulders, walls, and the chance of pelagics during the open season.
Phuket as an Andaman basecamp
Phuket is the easiest flightin hub for day boats, training reefs, and longer offshore routes.
Krabi and the Phi Phi island group
Combine Krabi and Koh Phi Phi for limestone scenery topside and reef and wall profiles that suit a wide range of experience levels.
Koh Tao and Chumphon pinnacles
Koh Tao is Thailand's course and dayboat engine.
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