Kamata, Ota City, Tokyo
Kamata Onsen
A traditional bathhouse known for its naturally dark mineral water, heated with firewood. The operator does not publish a fixed bath temperature, and older spring-analysis figures should not be treated as current.
Facility photos
Check before bathing
- Opening hours
- 10:00–24:00. Current adult admission is ¥600, primary-school children ¥200 and preschool children ¥100. Sauna costs an extra ¥300; a hands-free set is ¥900. Cash only. Usually open year-round, but check for temporary closures.
- Tattoo policy
- The current FAQ does not state a separate tattoo prohibition or guarantee acceptance. Check with the bathhouse before visiting if this matters to you.
Spring & water temperature
- Spring-source temperature
- Not published currently. A secondary 2009 source lists 17.5°C; this is historical, not a current measurement.
- Bathing temperature
- No fixed setting is published. The operator says the black bath can approach 50°C on some days; visitor reports of 42–43°C are observations, not guaranteed settings.
- Spring classification
- Sodium bicarbonate-chloride cold mineral spring.
- pH
- Not published currently. A secondary 2009 source lists pH 8.2; this is historical.
- Flow rate
- No current figure is published. A secondary 2009 source lists 50.4 L/min; treat it as historical.
- Water handling
- The operator says the black water is natural, undiluted and heated with firewood. Current official information does not give full circulation or disinfection details. The white bath, electric bath, jets and cold-water bath are separate from the black natural-spring water.
Historical analyses and visitor temperature reports do not establish current measurements or fixed daily settings. Babies may accompany an adult but should not be placed directly in the public bath. Mixed bathing is limited to children under 6; opposite-sex bathing is discouraged at or above 120 cm in height.
How to read a bath profile
Spring-source temperature and actual bathing temperature are kept separate. Each score is shown independently for comparison rather than collapsed into one overall score.
