Richelieu Rock is one of the most famous dive sites in Thailand. Richelieu Rock is an isolated pinnacle to te east of Surin Islands. The site is marked by the top of the pinnacle which is 1 meter above sea level at low tide and submerged at high tide. Forming a horseshoe the pinnacle falls steeply to the sourounding sandy bottom at a depth of 35 meters. The south side is a secured bay with a slope tht gently falls to the deep whereas the rest of Richelieu Rock comprises of sheer walls, rocks and small caves that are home to various marine life.