Stork Island/Koh Chi

The dive works the western side of the islet, a gentle slope of granite boulders running down to 22 m. Hard corals carpet the sea floor and large gorgonian fans stand off the rock where the water moves, so the profile is a staged descent along the boulders rather than a single level — the deeper ground first, then back up over the shallow coral as the gas budget allows.

Blacktip reef sharks are the dependable sighting: Dive The World rates this as a reliable site for them, and they are seen more frequently here than in the Similan Islands, where the species is absent. The north end of the islet is a jumble of granite boulders and caverns, and those refuges hold soldierfish, angelfish and reef sharks. Out in the water column, pelagic fish pass along the slope — trevally, barracuda and tuna — and several turtle species are seen on the reef.

Close in, the same ground reads as a macro dive. Nudibranchs, shrimps and crabs work the coral and the rubble margins, and that is where a lot of the bottom time goes once the sharks and the fans have been covered. Watch the current through the whole dive: Scubago describes it as strong and unpredictable rather than steady, so the safe finish is to stay with the guide and come up together rather than working the shallows alone.