Kusatsu Onsen, Kusatsu, Gunma Prefecture
Sainokawara Open-Air Bath, Kusatsu Onsen
The leading Kusatsu pick if scenery, a vast open-air bath and strongly acidic Bandai spring water matter most. It is not a one-stop bathhouse for washing, a hairdryer, indoor pools or a place to rest.
Check before bathing
- Opening hours
- 1 April–30 November: 07:00–20:00. 1 December–31 March: 09:00–20:00. Last admission is normally 19:30. On the second Wednesday of each month, the bath usually closes at 17:00, with last admission at 16:30; August is an exception. The announced early closure on 9 September 2026 has passed; check for new notices.
- Tattoo policy
- The current facility information reviewed does not confirm a tattoo policy. Contact the bath before visiting.
Spring & water temperature
- Spring-source temperature
- 94–95°C at the Bandai spring. This is the source temperature, not the open-air pool temperature.
- Bathing temperature
- Not published.
- Spring source
- Bandai spring.
- Spring classification
- Acidic chloride-sulfate spring.
- pH
- Not published in the current material summarized here.
- Flow rate
- Not published in the current material summarized here.
- Water handling
- The facility's FAQ confirms source-flowing spring water. This is an open-air bath only, with a combined area of about 500 m² across the men's and women's sides. The current main pages do not give complete details on water addition, heating, circulation or disinfection, so “source-flowing” is not expanded into a claim of no treatment at all.
Bathing indications
The facility lists general bathing indications including neuralgia, joint pain, bruises, sprains, burns, chronic digestive conditions, recovery after illness and chronic gynecological conditions. These are not treatment guarantees.
The facility confirms source flow; complete pool-treatment details are not published.
Admission is ¥800 for adults and ¥400 for children aged 3 through elementary school. There are no washing stations, hairdryers, rest area, restaurant, private baths or rental towels.
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.
