Diver journal mentioning Kumomi Ushitsukiiwa and common octopus sightings.
Kumomi Ushitsukiiwa: boat cave dive with rich life.
Kumomi Ushitsukiiwa: boat cave dive with rich life.
Kumomi Ushitsukiiwa is a boat dive in front of Kumomi harbor on the Izu Peninsula, built around two large rocks with caves and caverns between them. It combines soft corals, sea goldies, butterflyfish, and offshore schools of grunts with a route that suits guided boat dives and disciplined overhead-environment planning.
Conservative baseline from public research. No community dives logged yet.
Depth range, seasonality, and planning context.
Reported Depth
12m - 24m
Depth Note
Boat-dive routes average about 12-15 m, with advanced lines reaching around 24 m.
Best Season
Summer and autumn for the clearest visibility; year-round diving is possible.
Hazards, restrictions, and access requirements.
Key Hazards
Safety Notes
Treat it as a cave/cavern dive with overhead sections; keep your gas, buddy contact, and exit plan disciplined.
Access Restrictions
Boat access only; overhead sections require cave/cavern discipline and the right certification.
Legal Notes
Follow local boat-operator and harbor rules for the cave-diving area.
Community notes to help plan your visit.
Scuba Diving
A boat-access cave and cavern system with routes that range from novice to advanced profiles.
Freediving
Not a freedive target; the overhead sections and boat logistics make scuba the correct mode.
Snorkeling
Not a snorkel site; the best features are underwater caves, caverns, and the surrounding reef structure.
Species commonly reported at this site, with direct links into their wildlife guides.
Community dive logs and visit reports for this site.
Average conditions based on logged dives & visits.
Planning answers for access, conditions, timing, and site logistics.
Last Updated
Research Sources
Diver journal mentioning Kumomi Ushitsukiiwa and common octopus sightings.
Operator page with visibility, depth bands, and boat support for Kumomi cave dives.
Independent guide describing the two offshore rocks and the shallow reef character.
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