Koh Chueak & Koh Waen

Koh Chueak and Koh Waen are barely islands — a pair of limestone rocks pushing out of the water between Lanta and Koh Mook. What matters is what is underneath them.

Soft coral covers the walls in colours that hard coral never manages, and there is a short swim-through arch at Koh Chueak shallow enough to snorkel. Green turtles feed here often enough that most trips see one.

Both are open-water sites with some current, so they suit confident swimmers better than nervous ones. Life jackets are always available.