Koh Bon is located north of Similian Islands and offers world-class diving. The dive site is on the southwestern point and consists of a 33 meter wall facing the small cove, and a step-down ridge that carries on to depths of over 45 meters. Koh Bon is one of the better places to see manta rays, especially towards the end of the season when there is more plankton in the water. In that area you also have the islands Koh Tachai, the Surin Islands, and Richelieu Rock.