Koh Tachai is a beautiful island to the north of the Similans, approximately 20 kilometers north of Koh Bon. Koh Tachai is an island with white sand beaches and thriving vegetation and is home to a couple of good dive sites, one of which is Tachai Pinnacle.

The dive site Tachai Pinnacle is just south of the island and is marked by buoys on the water’s surface. Large boulders sit on a sandy bottom with depths of up to 45 meters.