Koh Bon Ridge
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
Koh Bon is a limestone island north of the Similans, and its western ridge is the most reliable manta dive in Thai waters. A rocky spine runs off the island's point and drops away into deep water, and reef mantas ride the current up to cleaning stations along it, sometimes hanging over divers in slow, close passes while wrasse pick them clean. Away from the mantas, the ridge and its wall gather schooling fusiliers, snapper and trevally, with white-tip reef sharks resting on the ledges and the occasional whale shark cruising past in season. The deeper pinnacle off the same island adds leopard sharks and bigger pelagics for those going down further. Current on the ridge is the whole point, since it is what draws the mantas in, but it can run hard and makes this an intermediate-and-up dive. The mantas are most consistent later in the northern Thailand season, roughly from February into May.
Local knowledge · DiveConnectMarine life here
Confirmed by our research team, reported by independent divers, or observed nearby via iNaturalist — each entry is labelled with its source.
Reef sharkReef sharkReported here · unconfirmed
Moray eelMoray eelReported here · unconfirmed
Titan TriggerfishBalistoides viridescensReported here · unconfirmed
Moorish IdolZanclus cornutusReported here · unconfirmed
Three-spot DascyllusDascyllus trimaculatusReported here · unconfirmed
Graeffe's Sea CucumberPearsonothuria graeffeiReported here · unconfirmed
Red-tailed ButterflyfishChaetodon collareReported here · unconfirmed
Giant MorayGymnothorax javanicusReported here · unconfirmed
Pixy HawkfishCirrhitichthys oxycephalusReported here · unconfirmed
Emperor AngelfishPomacanthus imperatorReported here · unconfirmed
SweetlipsSweetlipsReported here · unconfirmed
Manta rayManta rayConfirmed present · 2 independent sources
SnapperSnapperReported here · unconfirmed
OctopusOctopusReported here · unconfirmed
Leopard / zebra sharkLeopard / zebra sharkReported here · unconfirmed
TrevallyTrevallyReported here · unconfirmed
TunaTunaReported 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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