Semi-no-Yu in Semi Onsen: A Public Bath with Four Ways to Enjoy the Spring
Plan a visit to Semi-no-Yu in Semi Onsen: ¥500 admission, weekday cleaning hours, a steam-bathing room called fukashi-yu and a free footbath.
Checked: September 27, 2026
Semi Onsen is a compact hot-spring settlement in Mogami, and its communal bathhouse, Semi-no-Yu, has more going on than a single indoor pool. The building brings together an indoor bath, an outdoor bath, a traditional steam-bathing room known as fukashi-yu, and a free footbath outside. That unusual mix is the reason to stop here; it is not a full-service spa with a restaurant, hair dryers or a long list of amenities.
| Detail | Current information |
|---|---|
| Admission | ¥500 per person |
| Payment | Five ¥100 coins; no change machine inside |
| Monday–Saturday | 6:00–9:00 am and noon–11:00 pm; closed for cleaning 9:00 am–noon |
| Sunday | 6:00 am–11:00 pm, with no midday cleaning break |
| Lock-up | 11:00 pm |
| Indoor bath | Two pools, listed at about 43°C and 45°C |
| Fukashi-yu | Steam bath, up to five people at a time |
| JR access | About a 10-minute walk from JR Semi-Onsen Station |
What makes the bath different
The indoor Nagomi-no-Yu has two pools: one described as the moderate-temperature option at about 43°C and the other around 45°C. Even the “moderate” pool may feel hot if you are used to hotel baths closer to 40°C, so test the water gradually rather than treating either number as a long-soak target.
The outdoor Yagen-no-Yu uses a different spring from the indoor bath, according to Mogami Town. The town’s page describes the indoor bath as free-flowing from the source, but does not give a full, current breakdown of water treatment for every pool. Area-wide spring figures should not be mistaken for the temperature or treatment conditions of a particular tub.
Fukashi-yu is the feature most visitors will not have tried elsewhere. Instead of sitting in a hot-air sauna or getting into a pool, you sit or lie over a wooden floor where geothermal steam rises through openings. Up to five people can use it at once. Follow the posted instructions and keep a comfortable distance from the steam outlets; leave if the heat feels sharp or you become light-headed.
There is also a covered footbath by the entrance, free to use. Beside it, a spring-water area has space for making onsen eggs. The local tourism association says they take about an hour, so this only fits if you have time to wait rather than a train to catch.
Bring coins and check the cleaning break
The ¥500 entry is paid through a coin-operated entrance that requires five ¥100 coins. There is no change machine inside. Bring the right change before you arrive; a ¥500 coin or banknote alone may not get you through the gate.
From Monday to Saturday, the bath closes to visitors for cleaning between 9:00 am and noon. Sunday is the only day listed as open continuously from 6:00 am to 11:00 pm. Temporary closures have occurred for repairs: the tourism association posted a reopening notice on May 19, 2026, after a closure earlier that spring. If you are making a long trip specifically for Semi-no-Yu, check the latest notice on the day.
The facility is about a 10-minute walk from JR Semi-Onsen Station, making it manageable without a car. Train frequency is the constraint: confirm your return departure before you start bathing. Drivers have a small lot near the bath and another parking area about five minutes away, according to the prefectural listing.
Semi-no-Yu is a good fit if you enjoy community bathhouses and want to try more than a standard indoor soak. It is less convenient if you need toiletries, a hair dryer, electronic payment or an easy late-morning visit on a weekday. Current public information does not set out a tattoo policy; contact the Semi Onsen Ryokan Association if that matters to you.
For a simpler municipal bath with a private-bath option, see Akakura Yukemurikan. Onogawa’s Amayu and Taki-no-Yu offer a useful comparison if your route runs toward Yonezawa.
Sources
- [Mogami Town: Semi-no-Yu facilities and bathing options](https://town.mogami.lg.jp/culture/01rekishi-shiseki/47seminoyu.php) - [Mogami Tourism Association: Semi-no-Yu hours, admission and facilities](https://mogami-portal.net/spot/%E7%80%AC%E8%A6%8B%E6%B8%A9%E6%B3%89%E5%85%B1%E5%90%8C%E6%B5%B4%E5%A0%B4%E3%80%80%E3%81%9B%E3%81%BF%E3%81%AE%E6%B9%AF/) - [Mogami Tourism Association: day-use onsen guide and temporary-closure notices](https://mogami-portal.net/special/%E6%9C%80%E4%B8%8A%E7%94%BA%E6%97%A5%E5%B8%B0%E3%82%8A%E6%B8%A9%E6%B3%89%E3%82%B9%E3%83%9D%E3%83%83%E3%83%88/) - [Yamagata official tourism site: Semi-no-Yu access and parking](https://yamagatakanko.com/attractions/detail_10848.html) - [Mogami Town Tourism Association: reopening notice, May 19, 2026](https://mogami-portal.net/info/page/2/)Tags: Semi Onsen, Mogami, Yamagata public bath, fukashi-yu, day-use onsen
