The Japan resorts with the warmest sea water temperature at this moment are Nagasaki, Okinawa and Fukuoka.
Below you can see a list of all popular Japan resorts and information about current sea water temperature and averages for current and next months.
| Resort Name | Current Sea Water Temperature |
September 2025 | October 2025 |
|---|---|---|---|
| Nagasaki | 86.6°F | 87.7°F | 83.1°F |
| Okinawa | 86.4°F | 89.9°F | 88.5°F |
| Fukuoka | 85.8°F | 86.9°F | 79.4°F |
| Osaka | 85.4°F | 86.1°F | 77.0°F |
| Nara | 85.0°F | 86.2°F | 76.7°F |
| Kobe | 85.0°F | 85.0°F | 78.0°F |
| Hiroshima | 84.0°F | 84.9°F | 78.7°F |
| Nagoya | 84.0°F | 85.7°F | 77.3°F |
| Tokyo | 83.6°F | 85.1°F | 75.4°F |
| Kyoto | 83.6°F | 86.3°F | 76.0°F |
| Yokohama | 83.2°F | 84.3°F | 75.5°F |
| Kamakura | 83.0°F | 82.9°F | 76.9°F |
| Atami | 82.4°F | 83.0°F | 77.8°F |
| Hakone | 82.0°F | 82.7°F | 77.9°F |
| Sapporo | 74.4°F | 75.8°F | 66.7°F |
| Noboribetsu | 70.0°F | 73.5°F | 65.4°F |
Please see following sea water temperature averages charts for the warmest Japan resorts for more details.
You can also get the same information for the every other month of the year when the average sea water temperature is greater then 70°F.
