Bida Nai
Conditions & tides
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Marine forecast via Copernicus Marine. Score is a rule-based guide from swell/wind vs. the site's exposure — always dive your own assessment.
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About this site
Bida Nai is a small island situated to the south of Koh Phi Phi Ley, and is considered one of the best dive sites in the Phi Phi Islands area. The site is dived as a boat dive, and the best diving is concentrated on the western reef, with options to circumnavigate and take in the eastern side as well. It falls within the Mu Ko Phi Phi National Marine Park, and a park entrance fee applies.
The reef offers varied terrain depending on direction: the west and south slopes descend past large boulders and swim-throughs to a maximum depth of 30 m, while the eastern side opens onto large sandy bottoms and fields of Staghorn Coral. The shallowest reef comes up to around 5 m on the eastern side, and resting leopard sharks are found on sandy patches at around 20 m. Gorgonian sea fans, sea whips, and soft corals feature prominently throughout the reef structure.
Marine life at Bida Nai is diverse across all depth ranges. The western reef's cracks and crevices hide nudibranchs, ornate ghost pipefish, white-eyed morays, and seahorses. Black-tip reef sharks cruise the shallows at around 5 m on the east side, leopard sharks rest on sandy bottoms and also swim the western slopes, and turtles are regularly seen feeding on the shallow reef. Blue-spotted stingrays and bearded scorpionfish occupy sandy and rocky areas, while wrasse, parrotfish, and large schools of moorish idols dominate the shallower waters. Manta rays and whale sharks are known to visit periodically.
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Conditions are generally beginner-friendly, with light current, water temperatures of 27–30°C, and great visibility. The dive season runs from November to the end of April, with October to May cited as the broader window. The site is suitable for Open Water-certified divers and above, and is also used for Advanced Open Water course adventure dives.
Marine life here
Confirmed by our research team, reported by independent divers, or observed nearby via iNaturalist — each entry is labelled with its source.
BarracudaBarracudaConfirmed present · 2 independent sources
Sea turtleSea turtleReported here · unconfirmed
StingrayStingrayReported here · unconfirmed
Reef sharkReef sharkReported here · unconfirmed
Moray eelMoray eelReported here · unconfirmed
CuttlefishCuttlefishReported here · unconfirmed
Ornate ghost pipefishOrnate ghost pipefishReported here · unconfirmed
Ocellaris AnemonefishAmphiprion ocellarisReported here · unconfirmed
Long-spined Crown-of-ThornsAcanthaster planciReported here · unconfirmed
Clark's AnemonefishAmphiprion clarkiiReported here · unconfirmed
Banded Sea UrchinEchinothrix calamarisReported here · unconfirmed
Blackspotted PufferArothron nigropunctatusReported here · unconfirmed
Magnificent Sea AnemoneRadianthus magnificaReported here · unconfirmed
Indo-Pacific Sergeant MajorAbudefduf vaigiensisReported here · unconfirmed
Swarthy ParrotfishScarus nigerReported here · unconfirmed
Moorish IdolZanclus cornutusReported here · unconfirmed
Leopard / zebra sharkLeopard / zebra sharkConfirmed present · 6 independent sources
NudibranchNudibranchConfirmed present · 3 independent sources
FusilierFusilierReported here · unconfirmed
ParrotfishParrotfishConfirmed present · 2 independent sources
Whale SharkRhincodon typusConfirmed present · 3 independent sources
ScorpionfishScorpionfishConfirmed present · 3 independent sources
WrasseWrasseConfirmed present · 2 independent sources
OctopusOctopusConfirmed present · 2 independent sources
PufferfishPufferfishConfirmed present · 2 independent sources
SeahorseSeahorseReported here · unconfirmed
SquidSquidReported here · unconfirmed
Ghost pipefishGhost pipefishReported here · unconfirmed
LionfishLionfishReported here · unconfirmed
SnapperSnapperReported here · unconfirmed
PipefishPipefishReported here · unconfirmed
Manta rayManta rayConfirmed present · 2 independent sources
TrevallyTrevallyConfirmed present · 2 independent sources
ClownfishClownfishConfirmed present · 2 independent sources
TunaTunaReported here · unconfirmed
MackerelMackerelReported here · unconfirmed
Nurse sharkNurse sharkReported here · unconfirmed
AngelfishAngelfishReported here · unconfirmed
TriggerfishTriggerfishReported here · unconfirmed
Durable tips from divers — access, hazards, marine life, facilities. For day-of conditions, use the report tool in the conditions card above.
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