Phang Nga Bay Limestone Karsts and Phi Phi Islands Trips

While Phuket's west coast looks out toward the open Indian Ocean, its sheltered east coast faces one of the geological wonders of Southeast Asia: a drowned karst landscape where hundreds of vertical Permian limestone towers rise straight out of emerald and turquoise water. With only one full day for the water on a three-day Phuket itinerary, your big decision is choosing between the dramatic sea caves of Phang Nga Bay to the north-east and the white-sand coral lagoons of the Phi Phi or Racha Islands to the south-east.

Ao Phang Nga National Park (limestone sea stacks, hongs and Koh Panyee)

Stretching between northeastern Phuket, Phang Nga province and Krabi, Phang Nga Bay is almost entirely enclosed by land, meaning the water stays calm and flat even during the May-to-October green season when open-sea waves are rough. The bay is famous for its hongs (from the Thai word for "room"): collapsed internal caverns hidden inside hollow limestone islands that can only be entered by inflatable sea kayak through low tidal rock tunnels at the base of the cliffs.

• Hong Island (Koh Hong) and Panak Island: paddle silently beneath stalactite-hung rock ceilings into open-sky emerald lagoons ringed by sheer hundred-metre walls of jungle, hornbills and mangroves.
• Khao Phing Kan and Koh Tapu (James Bond Island): a needle-like twenty-metre limestone monolith balanced on a narrow rock pedestal in the shallow bay; book an early-bird departure from Phuket's east-coast marinas or a late-afternoon sunset boat to see the karst before midday tour flotillas arrive.
• Koh Panyee floating village: a Muslim fishing community built entirely on stilts in the shadow of a vertical rock cliff since the late eighteenth century, complete with a gold-domed mosque and a floating football pitch.

The Phi Phi Archipelago, Bamboo Island and Koh Racha

Forty-five kilometres south-east of Phuket's Rassada Pier across deeper, clearer blue water lie the twin islands of Koh Phi Phi Don and uninhabited Koh Phi Phi Leh. Here the attraction is crystalline water and coral reefs rather than mangrove caves: boats pause outside the towering limestone amphitheatre of Maya Bay (where swimming is strictly regulated by the national park to protect blacktip reef sharks and regenerating coral, and the bay closes annually in August and September for ecological recovery), glide into the emerald fjord of Pileh Lagoon, and anchor off the blindingly white sandbar of Bamboo Island (Koh Pai). If you prefer a shorter thirty-minute boat ride with less travel time and clear snorkelling straight off the sand, consider Koh Racha Yai or Coral Island (Koh Hey) just off Phuket's southern tip.