Hop Over to Ko Tao for Diving and Snorkeling

From the air, Ko Tao (the smallest of the three islands) looks like mounds of granite boulders cloaked in green, drifting on a jade-green sea and linked by dazzling sweeps of white-sand beach. Diving is the most popular thing to do here. Colorful coral reefs lace the clear waters that are home to some of the best diving spots in Southeast Asia. Vast schools of fish, brightly-colored sea anemones, stingrays, and even whale sharks are among the sea creatures spotted here, and the island is a popular and relatively affordable place to obtain PADI scuba diving certification.

Though it's certainly no off-the-beaten-path destination, Koh Tao typically has fewer tourists than both Samui and Phangan