Koh Tao
Thailand · Gulf of Thailand
Koh Tao is the budget diver capital of Asia — more Open Water certifications issued here per year than anywhere else on Earth. The diving is gentle granite boulder pinnacles in the Gulf of Thailand, with reef fish, turtles, and the occasional whale shark in season.
How this reef is doing
ⓘ How we measure thisReef state
Training mecca — shallow reefs near Sairee have thinned considerably. Whale sharks April–May the seasonal draw.
Coral cover
Fish life
Heat
Warmer than usual right now, but not hot enough to bleach.
Fishing
Protected on paper, but boats are still busy nearby.
Sources · MERMAID and partner coral surveys · NOAA Coral Reef Watch · Global Fishing Watch and reef gravity
What you will see
17 species across the dive sites here
Blue-Barred Parrotfish
Seen 25 days ago
at Chumphon Pinnacle
Least concern
Hong Kong Butterflyfish
Seen 25 days ago
at Chumphon Pinnacle
Least concern
Surf Parrotfish
Seen 25 days ago
at Chumphon Pinnacle
Least concern
Doublebar Rabbitfish
Seen 27 days ago
at Chumphon Pinnacle
Least concern
Greater Racket-Tailed Drongo
Seen 1 month ago
at Sail Rock
Least concern
Bigeye trevally
Seen 1 month ago
at Sail Rock
Least concern
Titan triggerfish
Seen 1 month ago
at HTMS Sattakut
Least concern
Yellowtail fusilier
Seen 1 month ago
at HTMS Sattakut
Least concern
Bull shark
Seen 1 month ago
at Chumphon Pinnacle
Vulnerable
Whale shark
Seen 1 month ago
at Sail Rock
Endangered
Fluted Giant Clam
Seen 2 months ago
at Sail Rock
Least concern
Calotes thailandensis
Seen 7 months ago
at Sail Rock
Great barracuda
Seen 11 months ago
at Chumphon Pinnacle
Least concern
Pink anemonefish
Seen Apr 2025
at Sail Rock
Least concern
Bluefin trevally
Seen year round
at HTMS Sattakut
Least concern
Giant grouper
Seen year round
at HTMS Sattakut
Schooling chevron barracuda
Seen year round
at Sail Rock
Dive sites
What divers say
I came for ten days for my Open Water and stayed three months. That's the Koh Tao story.
Good to know
Crowds
Major sites get busy. Ask your shop about smaller boats and off hours trips.