Itō Onsen
- Location
- Shizuoka -, Japan
- Water type
- sodium chloride
- Temperature
- 52 °C
- pH
- 7.8
Water profile
Relaxing — deep, immediate muscle release.
Loaded with major ions — the essential minerals (Ca, Mg).
Dense, salty water — you float without effort.
On the eastern coast of the Izu Peninsula, where the broad waters of Sagami Bay stretch toward the Izu Islands and the Pacific horizon, Itō Onsen is one of Shizuoka's most storied hot spring towns — a destination that has welcomed visitors since the feudal era, when the natural sodium-chloride waters of this coastline drew both travelers and rulers. The springs flow at an impressive 52 °C, rich in sodium-chloride at a mildly alkaline pH of 7.8, producing the classic kaen-no-yu — the warming flame bath — that sodium-rich onsen are celebrated for across Japan.
Itō's onsen town character is preserved in its network of public bathhouses, riverside ryokan, and footbaths that dot the city's promenade. The sodium-chloride waters leave a residual warmth that persists for hours after bathing, drawing cold-season visitors especially eager to carry the ocean-mineral heat through a full day of exploring the peninsula's coastal landscape and temples.