Big Wall
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
The Big Wall is a deep, vertical wall dive at Mnemba Atoll, off the north of Zanzibar. It drops from about 12 to 40 metres in one description and from 18 to 50 metres in another, and the wall bottoms out at 60 to 70 metres.
It is a drift dive, with a free descent to 30 to 35 metres and a current from nothing to very strong. Visibility can reach 30 metres. It is for Advanced Open Water divers who hold a deep diving qualification, and it can only be dived in good weather.
Schools of barracuda, rainbow runners, tuna, batfish and hundreds of unicornfish pass along the wall, with large Napoleon wrasse and blotched stingrays on the bottom. Small caves in the wall hold lobsters among yellow snappers and bigeyes. Octopuses, moray eels and mantis shrimps are on the reef.
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The dive ends in the shallows over coral gardens with hard and soft corals, where a whitetip reef shark may swim past over the sand.
Marine life here
Confirmed by our research team, reported by independent divers, or observed nearby via iNaturalist — each entry is labelled with its source.
StingrayStingrayReported here · unconfirmed
LobsterLobsterReported here · unconfirmed
Napoleon (humphead) wrasseNapoleon (humphead) wrasseConfirmed present · 4 independent sources
Jack / amberjackJack / amberjackConfirmed present · 2 independent sources
Moray eelMoray eelReported here · unconfirmed
Reef sharkReef sharkReported here · unconfirmed
Skunk AnemonefishAmphiprion akallopisosReported here · unconfirmed
Geometric MorayGymnothorax griseusReported here · unconfirmed
Spinner DolphinStenella longirostrisReported here · unconfirmed
Three-spot DascyllusDascyllus trimaculatusReported here · unconfirmed
Indo-Pacific Sergeant MajorAbudefduf vaigiensisReported here · unconfirmed
Guineafowl PufferArothron meleagrisReported here · unconfirmed
Blacklip ButterflyfishChaetodon kleiniiReported here · unconfirmed
Loch's ChromodorisChromodoris lochiReported here · unconfirmed
SnapperSnapperReported here · unconfirmed
OctopusOctopusConfirmed present · 2 independent sources
BatfishBatfishConfirmed present · 2 independent sources
UnicornfishUnicornfishConfirmed present · 2 independent sources
TunaTunaConfirmed present · 4 independent sources
BarracudaBarracudaConfirmed present · 3 independent sources
Indo-Pacific Bottlenose DolphinTursiops aduncusReported here · unconfirmed
Pacific TrumpetfishAulostomus chinensisReported here · unconfirmed
Moorish IdolZanclus cornutusReported here · unconfirmed
GrouperGrouperReported here · unconfirmed
Mantis shrimpMantis shrimpReported here · unconfirmed
Whale SharkRhincodon typusReported here · unconfirmed
Manta rayManta rayReported 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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