Just south west of Krabi coastline lie the stunning Phi Phi Islands, part of a marine national park that's one of the world's most unforgettable destinations. Phi Phi Don, the larger island, offers sheer limestone cliffs, fine sand beaches and hidden coves. Not far away, coral gardens and deeper reefs are sensational for diving and snorkeling. There are no cars on Phi Phi, just simple small tracks that crisscross the island, so getting around is easy – simply take a local longtail boat, or walk.
Smaller Phi Phi Leh is uninhabited and made up of steep limestone cliffs rising sheer out of the turquoise waters. It also features caves and small rocky coves. There are several bays ideal for shallow snorkeling, and on the northeast side, the famous Viking Cave, containing what are claimed to be prehistoric paintings. Phi Phi Leh is also a popular site for nesting swifts, and workers collect the nests used to make the lucrative bird's nest soup, a much-valued Chinese gourmet delicacy. Day trips to Phi Phi are easily available from Phuket and Krabi and offer snorkeling at Phi Phi Leh. If you are already on Phi Phi Don, it's possible to hire a local boat or join a tour to visit Phi Phi Leh.