Diving at the Similan Islands

Koh Bon

Manta Ray at Koh Bon

Koh Bon is located about 20km north of Similan Island #9 and features one of the only vertical walls in Thailand. The main dive site is on the southwestern point and has a step-down ridge that carries on to depths of over 45m. The eastern side of this ridge forms the wall and this is where most divers will enter the water and generally where the boats moor.

The western side of the ridge is more of a gentle slope with coral bommies forming mushroom-like formations out of the finger corals. On the ridge itself, seafans of different sizes, shapes and colors grow, and schooling fish swim in the current feeding. This is generally where most divers will sit most of the dive, hoping for a sighting of the manta rays which frequent this dive site. These creatures seem to travel from Bon to Tachai and back again during the diving season from October until May.

There is a pinnacle in the bay just to the north of the ridge. It's a deep rock but if you are an experienced diver it's worth the short bottom times you'll get as it's a very special site. Not all boats visit it and if conditions are not good (like the current is running strong), it's not worth the effort. But if the water is clear you're good with your air and the current is slack it's a stunning rock. It looks like a monolithic temple built by some ancient culture.