Trekking (Northern Thailand): A top draw for would-be adventurers, trekking is a great way to get out of the maze and get up among lush jungle terrain and meet with unique cultural experiences in hilltribe villages.
Rock climbing at Raillay Beach (Krabi): The dynamic karst cliffs above Krabi's Raillay beach make for some of the best sport rock-climbing in the world. But you don't have to be an expert. Beginners are welcome to sign up for an intro course and enjoy the challenge and the breathtaking views from on high.
Scuba diving: If you're not certified, Thailand is a great place to do it; scuba services are affordable yet offer a high standard of safety, and many large outfitters have long track-records in the business and experienced expat staff. The most popular centers -- Phuket, Ko Phi Phi, Ko Samui and nearby Ko Tao (almost strictly a divers island) -- have the largest concentration of operators to beautiful coral sites with lots of marine life. The best scuba operators offer all levels of PADI courses, daily junkets and longer stays on live-aboard trips-even short introduction dives for beginners.
Snorkeling just about anywhere: With huge living reefs and other odd creatures close to the water's surface, snorkeling in both the Andaman Sea and the Gulf of Thailand opens up under-the-sea wonders to anybody who can swim (or even just float). Check out Phuket's bays, Ko Phi Phi, areas around Krabi, Ko Samui, and islands along the eastern seaboard.
White-Water Rafting (Pai): Paddle through protected forests and along canyon walls lined with fossils and be carried over wild rapids as well as beautiful calmer stretches. Thai Adventure Rafting organizes exciting but safe tours just north of their office in laid-back little Pai.
