Bida Nok

Koh Phi Phi · Krabi · Thailand

Bida Nok is a small limestone island rising sharply from the Andaman Sea approximately two kilometres south of the main Phi Phi island group. Its sheer underwater walls, carpeted in sea fans and soft corals, make it one of the most visually striking dive sites in southern Thailand. The island's submerged cliffs drop from the surface to 28 metres where they meet a sandy slope scattered with coral bommies. The site is best known for its reliable leopard shark encounters. These docile bottom-dwellers rest on sandy ledges along the southern and eastern faces, typically at depths of 18 to 24 metres. During high season it is common to find three or four individuals on a single dive, lying motionless on the sand and allowing patient divers to observe them closely. Blacktip reef sharks also patrol the deeper sections, while banded sea kraits hunt through the reef crevices. The western wall is the site's visual centrepiece, covered in enormous purple and red sea fans that extend from the wall face like living parasols. Between the fans, dense clusters of soft corals in yellow, pink, and white create a colourful mosaic. Several swim-throughs cut through the limestone at various depths, their interiors filled with glassfish that shimmer in torch beams. Moray eels peer from holes along the wall, and octopuses change colour against the rock surface. The shallow reef on the northern side provides excellent conditions for safety stops and extended bottom time. Hard coral coverage here is impressive, with table corals, staghorn thickets, and brain corals supporting clouds of anthias and damselfish. Hawksbill turtles graze on the reef flat, and the nooks between corals hide nudibranchs, porcelain crabs, and ornate ghost pipefish that delight macro photographers. Morning visits offer the calmest seas and best visibility.