Kerama vs Ishigaki: Which Is More Consistently Clear?
2026-03-16
Kerama Islands and Ishigaki Island are Okinawa's two premier diving destinations. Known for 'Kerama Blue' and 'Ishigaki Blue' respectively, our data shows Ishigaki at 20.5m (1,473 obs) vs Kerama at 19.3m (1,554 obs) — Ishigaki leads by +1.2m. However, Kerama excels in consistency. We analyzed the data to help you choose.
20.5m
Ishigaki avg
19.3m
Kerama avg
21.9m
Ishigaki Apr peak
21.1m
Kerama Sep peak
Monthly Visibility Comparison
| Month | Kerama(m) | Ishigaki(m) | Diff |
|---|---|---|---|
| Jan | 18.5m | 20m | +1.5 |
| Feb | 18.8m | 20.5m | +1.7 |
| Mar | 19m | 21.2m | +2.2 |
| Apr | 19.5m | 21.9m | +2.4 |
| May | 19.8m | 21.5m | +1.7 |
| Jun | 18m | 19.8m | +1.8 |
| Jul | 19.2m | 20m | +0.8 |
| Aug | 19.5m | 20.2m | +0.7 |
| Sep | 21.1m | 20.8m | -0.3 |
| Oct | 20.5m | 20.5m | 0 |
| Nov | 19.8m | 20m | +0.2 |
| Dec | 18.8m | 19.5m | +0.7 |
Different Peak Seasons
Ishigaki: Spring Is Best (Apr 21.9m)
Ishigaki peaks in spring (March-May), with April reaching 21.9m — the annual high. Winter-cooled water stabilizes with low plankton, maintaining exceptional clarity. This overlaps with manta season (Oct-May), making spring Ishigaki an ideal combination.
Kerama: Autumn Is Best (Sep 21.1m)
Kerama peaks at 21.1m in September — the only month it surpasses Ishigaki. On calm days between typhoons, visibility can exceed 25m. Warm water temperatures allow comfortable diving in thin wetsuits.
Kerama's Consistency
Kerama's range is 18.0-21.1m (about 3m), remarkably stable. While Ishigaki's range is slightly tighter at 19.5-21.9m (about 2.4m), Kerama's floor never drops below 18m. You can count on 'Kerama Blue' any time of year.
Recommendations by Purpose
Choose Ishigaki When
- Want to see mantas (Oct-May)
- Targeting peak visibility (spring)
- Want a remote island diving experience
Choose Kerama When
- Want reliable visibility any time
- Day trip from Naha
- Best conditions in September
Access Comparison
| Factor | Kerama | Ishigaki |
|---|---|---|
| From Tokyo | Via Naha ~3.5h | Direct ~3h |
| Day trip | From Naha OK | Stay recommended |
| Sightseeing | Combine with Naha | Rich island tourism |
About the Data
Analysis based on real dive log data from Ishigaki (1,473 obs) and Kerama (1,554 obs). Visibility uses daily average values.
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