Thailand's a big enough country that you can find a place to practice almost any outdoor sport. Some selections:
Golf - see the separate Golf in Thailand article
Rock climbing - the cliffs of Rai Leh in Krabi are arguably among the best in the world
Scuba diving - easily accessible Ko Tao (near Samui) draws the crowds, but also possible in Pattaya and Krabi, and the Similan Islands are worth the journey
Trekking - very popular up north around Chiang Mai and Chiang Rai
Liveaboard Diving[6] see the separate Diving in Thailand article
Bicycle Tour[7]
Cycing in Thailand[8]
Spas see the separate Spas in Thailand article

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