Thailand – Koh Lanta & Krabi
Koh Lanta is the jump-off point for the southern Andaman's best-known open-water sites. Hin Daeng and Hin Muang, two isolated pinnacles far offshore, drop as steep walls covered in red and purple soft coral and are visited by manta rays and, in some seasons, whale sharks. Closer in, the small limestone group of Koh Haa offers a sheltered lagoon for beginners, cavern dives such as the Cathedral and the Chimney swim-through, while the twin Koh Rok islands are shallow, easy reef dives. From Ao Nang on the Krabi mainland, day boats visit the shallow islands of the bay, and Lanta-based centres also run trips south to the Trang islands. The Koh Phi Phi and Koh Bida sites are covered by the Phi Phi module.