Kumomi
Izu Peninsula · Japan
Kumomi sits on Izu's quieter western coast where cold Suruga Bay upwellings create exceptional water clarity and a remarkable density of invertebrate life on volcanic boulder fields. The site is celebrated for its extraordinary nudibranch diversity — well over 150 species have been logged here — alongside regular sightings of the strikingly patterned flamboyant cuttlefish. Far fewer divers make the drive out here than to eastern Izu sites, meaning marine life behaviour is largely undisturbed and encounters are unusually intimate.
Conditions
Depth
5 to 22 m
Open water and up
Current
Usually gentle
Can pick up on the edge
Visibility
6 to 12 m
Clearest in the calm season
Water
12 to 27°C
3mm wetsuit
Month by month
| Month | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Water (°C) | 13 | 12 | 13 | 15 | 18 | 20 | 22 | 24 | 22 | 19 | 16 | 14 |
| Vis (m) | 12 | 12 | 12 | 12 | 10 | 8 | 6 | 5 | 8 | 12 | 12 | 12 |
| Current | Still | Still | Still | Still | Gentle | Gentle | Gentle | Still | Still | Still | Still | Still |
Your chances of seeing each animal
Pacific Chub Mackerel
Last confirmed Apr 21, 2024 · 2 records
Rare
Now and then
Japanese Flying Squid
Last confirmed Apr 22, 2024 · 2 records
Rare
Now and then
Monodonta perplexa
Last confirmed May 21, 2026 · 2 records
Rare
Now and then
Skipjack Tuna
Last confirmed Apr 21, 2024 · 1 records
Rare
Now and then
Japanese Spurdog
Last confirmed Apr 22, 2024 · 1 records
Rare
Now and then
Chromodoris Nudibranch
Expected
Known here, not yet in recent logs
Coconut Octopus
Expected
Known here, not yet in recent logs
Flamboyant Cuttlefish
Expected
Known here, not yet in recent logs
Gear