Ao Nang is Krabi’s main centre for dive shops, with a dozen or more outlets, the most reputable of which include Kon-Tiki and Poseidon; they have a price agreement for PADI courses, but Poseidon is cheaper for dive trips. Diving with Ao Nang operators is possible year-round, with some dive staff claiming that off-season diving is more rewarding, not least because the sites are much less crowded.
Most one-day dive trips head for the area round Ko Phi Phi (from B3500 including two tanks; B1700 for snorkellers with Poseidon) and often include dives at Shark Point and the “King Cruiser” wreck dive (see Diving and snorkelling off Phuket); the Ko Ha island group, near Ko Lanta, is also popular but more expensive.
Two dives in the Ao Nang area – at Ko Poda and Ko Yawasam – cost B2700–3200 (B1900 for snorkellers), much less if you go in a longtail with Poseidon. PADI dive courses cost B5500 for the introductory Discover Scuba day, or B14,900 for the Openwater.
The nearest recompression chambers are on Phuket; check to see that your dive operator is insured to use one of them.