There’s some great snorkelling around Phi Phi’s shallow fringing reefs, most rewardingly at strikingly beautiful Ko Mai Pai (Bamboo Island), off Phi Phi Don’s northeast coast, where much of the reef lies close to the surface, and at nearby Ko Yung (Mosquito Island), with its spectacular, steep-sided drop. Phi Phi Don has its own worthwhile reefs too, including at west-coast Ao Yongkasem, within kayaking distance of Loh Dalum, but Ao Maya on Phi Phi Leh is more famous, and a lot more crowded.
Outings are easily arranged as part of an organized tour (B500–800 including equipment) or by hiring your own longtail boatman (B1500/3000 per boat per half/full day), the latter far preferable to the largest tour boats, whose groups of forty-plus trippers inundate the reefs. Overnight camping trips to Maya Bay are a neat way of avoiding the crowds, offering late-afternoon snorkelling, and possibly kayaking, rounded off with a beach barbecue.
Offering visibility touching 30m, a great diversity of healthy hard and soft corals, and potential encounters with white-tip sharks, moray eels and stingrays, the diving around Ko Phi Phi is the best in the area and the usual destination of dive boats from Ao Nang and Phuket. Highlights include the gorgonian sea fans, barracudas, manta rays and even whale sharks at Ko Bidah Nok and Ko Bidah Nai, the mass of leopard sharks at Hin Bidah, and the King Cruiser wreck.
There are at least twenty dive shops on Phi Phi, the majority of them in Ton Sai; seven of them have formed the Phi Phi Diving Association to promote eco-friendly, responsible and safe diving practices. Note that it’s considered risky for a novice diver with fewer than twenty dives to dive at Hin Daeng and Hin Muang, due to the depth and the current; reputable dive shops will only take Advanced Divers there. There are also small dive centres on Hat Yao, Ao Loh Bakao and Laem Tong.
Prices for day-trips including two tanks, equipment and lunch start at B2500, while the four-day PADI Openwater course costs B13,800. Check that your dive operator is insured to use one of the recompression chambers on Phuket.
The main rock-climbing area is just to the west of Ao Ton Sai, and includes the Ton Sai Tower and the Drinking Wall, with thirty routes from grades 5 to 7a. A newer attraction is deep-water soloing, unaided climbing on cliffs and outcrops over the sea.