Koh Tao Diving Guide: Everything You Need to Know

Koh Tao has earned its reputation as the dive certification capital of Asia — and arguably the world. The island's sheltered bays, relatively calm conditions, and abundance of reputable dive schools have made it the go-to place for PADI Open Water courses, which run around 9,000–10,500 THB including all equipment, theory, pool sessions, and four open-water dives. The most popular dive site for beginners is Koh Nang Yuan, a set of three islets connected by a sandbar with calm, clear water and good visibility. Hin Wong Bay, Shark Bay (White Rock), and Mango Bay are other reliable beginner-friendly sites.

For advanced and technical divers, Chumphon Pinnacle is the island's showpiece — a granite seamount rising from 40 metres that regularly draws whale sharks between March and September. Sail Rock (between Koh Tao and Koh Phangan) is the best single dive site in the Gulf of Thailand, with a dramatic chimney dive and near-guaranteed encounters with chevron barracuda, grouper, and seasonal whale sharks. There are around 60 dive schools on the island ranging from excellent (Crystal Dive, Big Blue, New Heaven) to mediocre — read recent TripAdvisor reviews, check instructor ratios, and visit the school in person before booking. Peak season is December–April and August–October; the shoulder monsoon months of May–June and November offer cheaper prices and smaller classes.