The island of Koh Tachai is located north of the archipelago of the Similan Islands. about 30 nautical miles. It is almost halfway between the Similan archipelago and the Surin Islands National Park. The tip of Koh Tachai is the only unique dive site near the island. It is located at the extreme south of the island. The position of the dive site, at the end of the rocky point is conducive to strong currents. These currents favor the concentration of schools of fish.

The abundance of underwater life, the biomass that is concentrated in this place is truly exceptional. Few places in the world concentrate so much life throughout the year. Schools of glassfish and alvins of all kinds mix with schools of fusiliers, Ignobilis trevallies, bigeye trevallies and even tuna. Basically, looking up, you may no longer see the surface or even the sun so the schools of fish are numerous and dense. This underwater abundance attracts the largest marine animals such as manta rays of reef and ocean, but also whale sharks.

The reefs at the Koh Tachai pinnacle have nothing to envy to the biomass present in open water. The biodiversity there is also impressive. Whether in wildlife fixed on the reefs or in the water column near the bottom. In some places, like a large carpet moving with the flow of the current and attacks of trevallies, the dense and compact schools of glassfish completely cover the bottom of the reef to the point of not seeing the corals lining the rocks. The abundance of soft corals with all colors of the rainbow spectrum creates a multicolored mosaic that enchants this exceptional coral reef.