Muroto & Kannoura Diving Visibility — Eastern Kochi's True Potential
2026-03-16
Muroto and Kannoura in eastern Kochi are among the closest mainland dive sites to the Kuroshio Current. Yet they trail same-prefecture Kashiwajima (avg 13.1m) by 4–5m. Why the gap? We analyzed 142 (Muroto) and 747 (Kannoura) real observations to find out.
Two-Site Comparison
Kannoura
9.1m
747 obs / Peak: Nov 11.5m
Muroto
8.8m
142 obs / Peak: Dec 10.9m
Kashiwajima (ref)
13.1m
1,499 obs / Peak: Jan 16.8m
Monthly Visibility Heatmap
| Site | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Kannoura | 11.1 | 11.3 | 7.1 | 7.3 | 8.2 | 9.6 | 9.3 | 7.2 | 8.4 | 8.5 | 11.5 | 11.2 |
| Muroto | 10.3 | 10.7 | 7.5 | 6.8 | 7.4 | 7.4 | 9.3 | 5.3 | 6.8 | 9.7 | 10.3 | 10.9 |
Why They Trail Kashiwajima by 5m
1. Different Kuroshio Exposure
Kashiwajima sits southwest of Cape Ashizuri where Kuroshio warm water flows in directly. Muroto and Kannoura are northeast of Cape Muroto — shielded from the main Kuroshio flow. Cape Muroto acts as a barrier, blocking clear oceanic water. (JMA Kuroshio Monitoring)
2. River Runoff Impact
Kannoura sits near the Nonegawa river mouth, making it susceptible to freshwater and sediment after rain. March–April (7.1–7.3m) combines snowmelt and spring rain. Kashiwajima has no major rivers nearby.
3. They Shine Only in Winter
Kannoura hits 11m+ from November to February — its annual best. Winter reduces river flow and increases Kuroshio approach frequency. Muroto also peaks in December (10.9m). The rule: visit eastern Kochi in winter.
About the Data
Muroto 142 / Kannoura 747 real observations (2006–Mar 2026). Kashiwajima 1,499 obs for comparison.
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