Conditions & tides
Scored by DiveConnect's site-physics model
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
Yonhon Iwa (四本岩) is a pinnacle site five minutes by boat from Hahajima in the Ogasawara Islands, Tokyo, with a maximum depth of 18 m. Schools of dogtooth tuna circle in the lee of the towering rock and can be watched at close range, and giant trevally and sand tiger sharks are sometimes present, with striped large-eye bream, bluestripe snapper, coral trout, cornetfish and spiny lobster on the rock. Current runs more often than not; the site is suitable from beginner level.
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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