The Japan resorts with the warmest sea water temperature in October are Okinawa, Nagasaki and Kobe.
Below you can see a list of all popular Japan resorts and information about sea water temperature in October for the last two years.
| Resort Name | October 2026 | October 2025 | October 2024 |
|---|---|---|---|
| Okinawa | 86.0°F | 88.5°F | 86.6°F |
| Nagasaki | 80.0°F | 83.1°F | 81.6°F |
| Kobe | 79.7°F | 78.0°F | 78.7°F |
| Osaka | 79.7°F | 77.0°F | 78.4°F |
| Nara | 78.4°F | 76.7°F | 77.7°F |
| Hiroshima | 78.4°F | 78.7°F | 79.3°F |
| Atami | 78.1°F | 77.8°F | 79.4°F |
| Nagoya | 77.9°F | 77.3°F | 78.9°F |
| Hakone | 77.7°F | 77.9°F | 78.6°F |
| Fukuoka | 77.3°F | 79.4°F | 77.7°F |
| Kamakura | 76.6°F | 76.9°F | 77.5°F |
| Yokohama | 75.9°F | 75.5°F | 75.6°F |
| Kyoto | 75.3°F | 76.0°F | 76.2°F |
| Tokyo | 74.8°F | 75.4°F | 75.7°F |
| Sapporo | 65.2°F | 66.7°F | 65.9°F |
| Noboribetsu | 62.4°F | 65.4°F | 66.2°F |
Please see following sea water temperature averages charts for the warmest Japan resorts in October.
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.
