Ko Tachai is the island located about half-way from Ko Bon up north to Richelieu Rock. The highlight of this corner of the Similans is the Tachai Pinnacle, also named “The Dome” as the shape of the pinnacle is rather wide with a very round flat top at around 14m depth.

Some dive operators also refer to the dive site as “Twin Peaks” as there is a second pinnacle just a short distance north of the Dome. The main pinnacle however offers more to see than can be explored on a single dive. For photographers, Ko Tachai is one of the key spots to tick off their luscious red soft coral and sea fan reef pictures ;).