Koh Bon

Koh Bon is a beginner-friendly dive site in the Andaman Sea that offers accessible reef diving around a small island south of the main Similan Island chain. Not to be confused with the Koh Bon within the Similan National Park boundaries, this site provides an excellent introduction to Andaman Sea diving with gentle conditions, healthy coral reefs, and the warm, clear water that characterizes Thailand's western coastline. The island creates a natural shelter on its leeward side, providing calm conditions that make entry and exit comfortable for less experienced divers. The reef extends from the shallow fringing zone near the island's rocky shore down to moderate depths, offering a gentle dive profile that maximizes bottom time and allows thorough exploration of the reef ecosystem. The underwater terrain mixes granite boulders with coral gardens, creating the habitat diversity that makes Andaman sites so rich in marine life. Coral coverage at Koh Bon is impressive, with hard corals forming a healthy reef framework and soft corals adding color and movement. Table corals extend their broad plates to capture sunlight, while branching corals create thickets that shelter juvenile fish. Sea fans in shades of red and purple extend from the granite surfaces, and barrel sponges punctuate the reef with their distinctive cylindrical forms. Marine life around the island is abundant and approachable. Schools of fusiliers create shimmering curtains of movement in the water column, while snappers congregate in loose groups around the larger coral formations. Angelfish and butterflyfish add color as they pick their way across the reef, and the granite boulders shelter moray eels, octopus, and various species of grouper. Hawksbill turtles occasionally visit to feed on the sponges that grow between the corals. The sandy patches between reef sections are worth investigating for divers interested in bottom-dwelling creatures. Blue-spotted stingrays rest on the sand, their distinctive spots making them one of the easier species to identify. Gobies maintain their shared burrows with pistol shrimp, and garden eels sway in colonies, retreating into the sand when divers approach too closely. Visibility at Koh Bon is typically good, benefiting from the clear oceanic water of the Andaman Sea. The diving season runs from November through April, when the northeast monsoon brings the calmest conditions and best visibility. Water temperatures remain warm throughout the season, making diving comfortable in minimal exposure protection. Koh Bon delivers a satisfying introduction to the Andaman Sea's underwater world. The combination of easy diving conditions, healthy reef ecosystems, and diverse marine life makes it an ideal site for building confidence and developing appreciation for the tropical marine environment that awaits at more advanced sites further offshore.