The Grotto
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
The Grotto is a well-known dive site on the east coast of Saipan in the Northern Mariana Islands, formed by a limestone sinkhole with three underwater openings connecting to the open ocean. Divers descend a set of stairs into the enclosed pool before passing through the channels into deeper water, and the site is known for dramatic light effects as sunlight filters through the openings. Maximum depth is around 22 metres, and it is rated an intermediate dive over a cave bottom. The stairs down into the sinkhole are steep, and winter months can bring rough waves that make entries and exits harder to time. Divers have reported barracuda, humphead wrasse, nudibranchs, and trevally moving through the chambers and channels.
AI overviewMarine life here
Confirmed by our research team, reported by independent divers, or observed nearby via iNaturalist — each entry is labelled with its source.
Princess DamselPomacentrus vaiuliReported here · unconfirmed
Dusky SurgeonfishAcanthurus nigrofuscusReported here · unconfirmed
Arc-eye HawkfishParacirrhites arcatusReported here · unconfirmed
Fivestripe WrasseThalassoma quinquevittatumReported here · unconfirmed
Leptastrea purpureaReported here · unconfirmed
Pacific Orange-spine UnicornfishNaso lituratusReported here · unconfirmed
Reticulated DamselfishDascyllus reticulatusReported here · unconfirmed
NudibranchNudibranchReported here · unconfirmed
TrevallyTrevallyReported here · unconfirmed
Napoleon (humphead) wrasseNapoleon (humphead) wrasseReported here · unconfirmed
BarracudaBarracudaReported here · unconfirmed
Blue DragonPteraeolidia semperiObserved near here · iNaturalist
Spotted TobyCanthigaster solandriObserved near here · iNaturalist
Green Sea TurtleChelonia mydasObserved near here · iNaturalist
Threespot WrasseHalichoeres trimaculatusObserved near here · iNaturalist
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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