Mantenboshi-no-Yu: A Day-Use Onsen Guide to Sarugakyo

Mantenboshi-no-Yu makes most sense when you want more than a quick bath. Its two gender-separated bathing areas look out towards Akaya Lake, and the building also has a large free rest hall, a restaurant and a sauna. A three-hour adult ticket is ¥950 (about HK$47 / NT$195); longer tickets are available if you plan to eat or stay awhile.

The practical details are easy to miss in older listings: the bath areas alternate by day, Tuesday is the usual closing day, and the facility does not admit guests with tattoos, tattoo stickers or body paint. If you are arriving by bus, check the return service before settling in. The timetable changes seasonally.

Admission, hours and weekly closure

The facility currently lists these admission options. Adult prices include the ¥50 bathing tax; child rates apply from age three through elementary school.

The usual hours are 10 a.m.–8 p.m. on weekdays, with last entry at 7 p.m.; on Saturdays, Sundays and public holidays, it closes at 9 p.m., with last entry at 8 p.m. It is normally closed on Tuesdays, except when Tuesday is a public holiday. The operator says hours and services can change, so check its notice or call before making a long trip.

The three-hour ticket is enough for a bath, a meal and a short break. Choose the longer stay if you want more time in the rest hall without watching the clock.

Two bath areas, one available to each gender per day

Mantenboshi-no-Yu has two public bathing areas, Sato-no-Yu and Tanabata-no-Yu. They switch between the men’s and women’s sides each day, so visitors of the same gender will use the same area that day. You cannot visit both in one session simply by moving between rooms.

Sato-no-Yu has a stone-garden setting and a reclining bath. Tanabata-no-Yu uses a more Western-style stone interior and has a jacuzzi in its outdoor section. Both sides have indoor baths, a warmer low-temperature bath and a sauna; the facility names its sauna a bona sauna. The main draw outside is the view across Akaya Lake and the surrounding hills. Which bath you get depends on the day’s rotation, so ask if one specific feature matters to you.

The operator identifies the source as Kyōyūsen Yujima, at 58°C, and describes the spring as calcium-sodium sulfate water, a weakly alkaline, low-tonicity, high-temperature spring. That source reading is not the bathing temperature. The facility also says that every bath is drained after closing, cleaned and refilled with hot-spring water daily. This is useful information about its cleaning routine, but it does not by itself establish whether every tub is otherwise used without circulation, heating, dilution or disinfection; those details are not fully published by tub.

A long visit has somewhere to go between baths

The free second-floor rest hall is about 110 tatami mats in size. There is also a ground-floor lounge, massage chairs and a restaurant overlooking the lake. The tourism association lists handmade soba and meals using local ingredients such as Joshu wheat pork; hours and menus may vary, so do not treat a specific dish as guaranteed.

Families or small groups can reserve the separate private bath, which has a natural-wood tub and washing area. It costs ¥3,000 (about HK$149 / NT$616) for 90 minutes, with admission charged separately, and advance booking is required. The private bath does not override the facility’s entry rules: its current notice excludes people with tattoos, tattoo stickers or body paint from entering. It also asks that children of elementary-school age and older use the bath for their own gender rather than bathing with a parent of another gender.

Getting there by bus or car

Kan-Etsu Kotsu buses run from Jomo-Kogen Station and Gokan Station towards Sarugakyo. The facility lists two useful stops: Mantenboshi-no-Yu Shita, followed by about five minutes on foot up a staircase, or Sekisho-ato, followed by a roughly seven-minute walk. The published Sarugakyo timetable currently covers April 1 through December 15, 2026. Check the schedule for your exact travel date and both directions; a late soak is not useful if the return bus has already gone.

By car, the facility’s access page gives about 20 minutes from Tsukiyono Interchange via National Route 17 and says there are two parking areas. It specifically advises drivers to bring snow equipment in winter. If the road is snowy or icy and you do not have mountain-driving experience, consider travelling by bus or choosing a daytime visit instead.

Is this the right Sarugakyo bath for your day?

Mantenboshi is the clearest choice in Sarugakyo if you want facilities around the bath: a sauna, dining, a large place to rest and several ticket lengths. It is less suitable for a quick late-evening stop on a weekday, or for anyone who needs a tattoo exception. For a simpler, lower-cost bath, compare it with the smaller facilities in our Sarugakyo day-use comparison. For other parts of Minakami, see the Minakami day-use onsen guide.

Sources and date checked

- Mantenboshi-no-Yu official site: [bath information, source and ticket table](https://www.mantenboshinoyu.com/furo.html), [facility guide](https://www.mantenboshinoyu.com/info.html), [current operating notices](https://www.mantenboshinoyu.com/), and [access and bus stops](https://www.mantenboshinoyu.com/access.html). - Minakami Tourism Association: [Mantenboshi-no-Yu facility listing](https://www.enjoy-minakami.jp/spot/7657/) and [Sarugakyo bus timetable, valid April 1–December 15, 2026](https://www.enjoy-minakami.jp/pdf/20260401sarugakyo.pdf). - Indicative currency conversions checked September 28, 2026: [JPY/HKD](https://ca.investing.com/currencies/jpy-hkd-historical-data) and [JPY/TWD](https://www.investing.com/currencies/jpy-twd-historical-data).

Checked: September 28, 2026.