Peace-yu in Nishi-Oi: Soft Water Through the Baths, Showers and Plunge
Peace-yu uses softened well water throughout, including showers and the cold plunge. This Nishi-Oi sento also has an electric bath and a ¥350 dry sauna.
Peace-yu’s defining feature is easy to overlook in a list of jets and tubs: the bathhouse softens its well water throughout the facility. The baths, showers and washing taps all use softened water, so the difference is part of the whole visit rather than one special pool. This is not a natural hot spring, but it gives the neighbourhood sento a water profile of its own.
Softened water is the through-line
The water begins as well water and goes through a softening system. It is neither untreated tap water nor a certified natural hot spring. Visitors sometimes describe softened water as feeling unusually slick, which can make soap seem harder to rinse away; that is a sensory difference, not a claim of medical or skincare benefit.
The bathhouse has a range of indoor pools, including jet, reclining and electric baths, plus a semi-open rock bath around 40°C. Its sauna is a traditional far-infrared dry type, without automatic steam or a programmed aufguss show. The cold plunge also uses the softened water. Temperatures noted by visitors vary, so treat any single reading as a snapshot rather than a fixed setting.
The electric bath is described as stronger than average. Ease in from the edge instead of leaning straight against the electrodes. Anyone with a pacemaker or relevant health concerns should skip it unless a clinician has said it is suitable.
Fees and a small timetable wrinkle
| Item | Price |
|---|---|
| Adult bath admission | ¥600 |
| Sauna add-on | ¥350; ¥950 total with bath admission |
| Small towel rental | ¥30 |
| Towel set | ¥100 |
| Shampoo and body wash | Provided |
| Listing | Hours and closure |
|---|---|
| Shinagawa Bathhouse Association | Tuesday–Friday, 3:30 p.m.–midnight; weekends and public holidays, 1:30 p.m.–midnight. Normally closed Monday; opens at 1:30 p.m. when Monday is a holiday. |
| Tokyo Sento Association directory | Lists Monday and Tuesday as closing days |
The directories disagree about Tuesday. Call ahead if that is your only possible visit day.
Nishi-Oi, Magome and Nakanobu stations are each about an eight-minute walk away. The balanced access makes Peace-yu handy from several neighbourhoods, though it is not a station-front stop. It is a better choice for someone curious about water feel and varied bath types than for a traveller seeking natural spring water or a large, fully open-air view.
For a nearby facility that does use natural hot-spring water, see Matsunoyu in Nakanobu.
Sources
- [Shinagawa Bathhouse Association: Peace-yu, current hours and fees](https://shinagawa1010.jp/list/peaceyu/) - [Tokyo Sento Association: Peace-yu facilities and current directory details](https://www.1010.or.jp/map/item/item-cnt-416) - [Tokyo Sento Association: “All soft water” Peace-yu feature](https://www.1010.or.jp/mag-tokyosento-comic-65-peaceyu/) - [Chill+: Peace-yu facility details](https://chillplus.jp/spot/peace-yu) - [Tokyo Sento Association: adult bathing fee from August 1, 2026](https://www.1010.or.jp/guide/%E5%85%A5%E6%B5%B4%E6%96%99%E9%87%91%E3%81%AE%E3%81%8A%E7%9F%A5%E3%82%89%E3%81%9B/) Checked: 2026-09-27Tags: Peace-yu, Nishi-Oi sento, Tokyo soft water, Shinagawa sauna
