Southwest Pinnacle

Nothing here breaks the surface, so the dive opens with a descent onto the main pinnacle, whose crown sits at about 5 m. From there the rock steps down to sand at 30 m, with six smaller pinnacles standing around it. Being out in open water rather than on a fringing reef is what makes this a site for experienced divers, whatever depth is worked on the day.

The granite is covered rather than bare: anemones, whip corals and sea fans grow across the sides, and marble grouper hold on the rock. Barracuda and jacks school off the pinnacles in mid-water, blue-spotted stingrays and leopard sharks are found down on the sand, and butterflyfish and blue-ringed angelfish work the shallower granite. Whale sharks have been recorded here, as on the other offshore pinnacles around Koh Tao.

The ascent is easier to manage than the depth suggests. Because the shallowest rock stands at 5 m you work up the pinnacle as air allows and hang the safety stop against it rather than in open water. Depth is what makes the site demanding, not the terrain: the sand at 30 m is well past the 18 m Open Water limit, so the deeper passes belong to divers with Advanced-level training.