Tsunashima Onsen
- Location
- Yokohama, Kanagawa, Japan
- Water type
- sodium chloride
- Temperature
- 40 °C
- pH
- 7.3
Water profile
Relaxing — deep, immediate muscle release.
Loaded with major ions — the essential minerals (Ca, Mg).
Dense, salty water — you float without effort.
Tsunashima Onsen is a historic hot spring in the Tsunashima and Tarumachi areas of Kohoku Ward, Yokohama, Kanagawa Prefecture, once celebrated as the back parlor of Tokyo for its role as a popular resort destination for urban residents who came to soak in the thermal waters and enjoy the rural atmosphere of the Tsurumi River valley before the area became one of the most densely developed suburban residential zones in the greater Tokyo-Yokohama metropolitan area. At its peak in the prewar and immediate postwar decades, Tsunashima Onsen hosted a flourishing hot spring resort culture with multiple ryokan inns, communal baths, and entertainment venues along the river, but the relentless urbanization of the Yokohama suburbs gradually absorbed the once-rural landscape, leaving only a handful of day-bathing facilities and hot spring sentos as remnants of its resort heritage. Today these surviving hot spring public baths preserve the memory of Tsunashima's resort past within a residential neighborhood that shows almost no trace of the rural spa community that once made it a beloved escape from the Tokyo megacity.