Osezaki Bay's Consistency: The Value of a Site That Never Disappoints
2026-03-16
You rarely hear 'amazing visibility at Osezaki Bay.' With a 7.6m average and 54.6% of days under 8m, the numbers look underwhelming. But this 'boringness' is Osezaki Bay's greatest strength. Its 2.0m monthly spread — the smallest in Japan — provides an ideal environment for training, macro photography, and refresher dives.
Monthly Visibility Pattern
| Month | Avg Vis |
|---|---|
| Jan | 11.8m |
| Feb | 10.5m |
| Mar | 9.2m |
| Apr | 8.4m |
| May | 7.8m |
| Jun | 7.1m |
| Jul | 6.4m |
| Aug | 5.9m |
| Sep | 6.5m |
| Oct | 7.3m |
| Nov | 8.9m |
| Dec | 10.8m |
Monthly Range: 5.9m–11.8m (Just 5.9m Spread)
The gap between clearest January (11.8m) and most turbid August (5.9m) is just 5.9m across months. Day-to-day variation within each month is even smaller, with a monthly average spread of 2.0m.
Comparison with Popular Izu Sites
| Site | Avg | Spread | Sub-8m % |
|---|---|---|---|
| Osezaki Bay | 7.6m | 2m | 54.6% |
| Mikomoto | 12.3m | 6.1m | 18.2% |
| Futo | 12.1m | 5m | 15.8% |
| IOP | 15.3m | 4.8m | 8.3% |
Mikomoto's 6.1m spread is 3x Osezaki Bay's. Mikomoto is a 'great when it hits, disappointing when it doesn't' site, while Osezaki Bay is 'roughly the same every time.' Choosing based on your goal matters.
When Stability Shines
Dive Training
Training courses need to run on schedule regardless of conditions. At Osezaki Bay, the risk of 'too murky for training today' is extremely low.
Macro Photography
For macro photography, biodiversity and stable underwater conditions matter more than visibility. Osezaki Bay's abundant macro life and calm conditions let you focus on shooting.
Refresher / Returning Divers
Rough seas after a long break are stressful. Osezaki Bay's calm conditions and predictable visibility provide reassurance for returning divers.
About the Data
Osezaki Bay visibility data collected from dive shop blog posts. Monthly average range (difference between best and worst month) used as stability metric. Comparison sites are all from the Izu area.
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