Sail Rock (Gulf of Thailand)

Sail Rock sits between Koh Tao and Koh Phangan, famous for its chimney swim-through and reliable big-fish traffic. Whale shark sightings spike from late March through May, especially on calm, sunny days with plankton-rich water. Depths range from 5 to 40 meters with variable currents around the rock’s shoulders. While experienced Open Water divers can join with close supervision, Advanced Open Water is recommended to enjoy the deeper terraces and manage drift. Expect schools of trevally, queenfish, and barracuda, plus healthy anemone gardens. Arrive early to avoid crowds, follow mooring-line descents when current runs, and keep 3–4 meters from any passing shark to avoid cutting off its route.