Green Rock
หินเขียว
Cave Explorer's Playground
A labyrinth of swim-throughs, caves, and overhangs formed by massive granite boulders — the most adventurous reef dive on Koh Tao.
Depth Range
2–28m
Site Type
reef
Koh Tao & Offshore
Visibility
8–25m
27–30°C
Getting There
15 min boat from Koh Tao
North of Koh Nang Yuan
16 Aug
17 Aug
18 Aug
19 Aug
20 Aug
21 Aug
22 Aug
Marine Life
Notable Features
- • Extensive cave and swim-through network
- • Glassfish-filled caverns
- • Unpredictable currents
Best Time to Visit
About Green Rock
Green Rock is a giant pile of granite boulders north of Koh Nang Yuan that has created an intricate network of swim-throughs, caverns, and overhangs. Penetrating the gaps between boulders reveals hidden chambers filled with glassfish, sleeping nurse sharks, and colorful soft corals. The deeper sections drop to 28m where large groupers and schools of snapper congregate. Currents can be unpredictable, adding to the excitement.
Tips
Bring a torch to illuminate the caverns. Watch for current — it can shift direction quickly here.
Experience Required
Intermediate to advanced. Comfortable with overhead environments.
Location
GPS: 10.1260°N, 99.8100°E
Learn to Freedive in the Gulf of Thailand
Sites like Green Rock are what the Gulf has to offer. Get certified with us on Koh Samui — train at Sail Rock and Koh Tao in groups of no more than 3, skip the Koh Tao ferry, and dive the best of the region.
New to freediving? Get the free beginner's guide first.