Koh Tan: Coral Island Quiet — Snorkeling, Speedboats, and Pig-Studded Beaches off Koh Samui

The wooden prow of the longtail slips through a channel of glassy blue, and the island that appears is almost too tidy to be real: a crescent of pale sand, a fringe of palms, and reef flats that shift from turquoise to cobalt like an artist blending pigment. You step off into a warm, low tide that exposes coral bommies and star-shaped anemones; the engine gives a final cough and the boatman ties a rope to the beach, as if to secure you to a simpler world. This is Koh Tan—often written Koh Taen—the low, coral-made sibling of Koh Samui. It’s not built for resorts or noise. It exists to be swum to, snorkeled over, and skimmed past on a day trip from the island where most visitors sleep.