Right Onsen › Gunma › Shimonita
Yachiyo Onsen Seri-no-Yu
4.2★ · 552 Google ratings · Shimonita, Gunma · 八千代温泉 芹の湯
✓ Day visitors
Before you go
Can you bathe here?
Day visitors
✓ YesStated on the facility's website
Hours
11:00–20:00From the facility's listing
Closed
Thursdays, 2nd FridayStated on the facility's website
Tattoos
? Call aheadNo policy stated in the 36 recent reviews we read or on the facility's website
Price
¥800 adultConfirmed by recent visitor reports
Child price
¥500Stated on the facility's website
Bathing
Men and women separateConfirmed by recent visitor reports
How we know this
- Day visitors: The inn used to offer lodging but is now day-use only. · stated on the facility's website, read 2026-09 · 2 visitors, May 2026
- Closed: stated on the facility's website, read 2026-09
- Price: Current adult admission is consistently 800 yen (it was 500 yen in 2022 and 700 yen in 2023 per one long-time reviewer's history). · 5 visitors, Jan 2026 – Aug 2026
- Child price: stated on the facility's website, read 2026-09
- Bathing arrangement: Men's and women's baths are separate but swap rooms daily. · 3 visitors, Jan 2026 – May 2026
The bath
What you’ll find
A remote, rustic day-only hidden-gem bathhouse in Shimonita with a strongly saline, slippery carbonated chloride-bicarbonate spring, indoor-only tubs that swap gender daily, a beloved shop dog, and a restaurant, but no rest area and one detailed review reporting real ventilation/oxygen problems in the sealed bathroom.
Bath setup
Indoor baths
2.0Reported by two visitors
Outdoor bath
✕ NoReported by two visitors
Sauna
✕ NoReported by one visitor
Spring water
Spring type
sodium chloride-bicarbonate cold mineral springReported by two visitors
Source temperature
13.8°CReported by two visitors
pH
pH 6.3Reported by two visitors
Free-flowing (kakenagashi)
Partly confirmedFresh spring water flows continuously through the bath
Heated
✓ YesConfirmed by recent visitor reports
How we know this
- Indoor baths: Two indoor tubs (a stone one and a cypress-wood one) that swap between men's and women's use daily. · 2 visitors, Jan 2026
- Outdoor bath: Baths are indoor only, no outdoor bath and no sauna. · 2 visitors, Jan 2026 – Jun 2026
- Sauna: No sauna on site. · 1 visitor, Jun 2026
- Spring type: Officially classified as a carbonated sodium chloride-bicarbonate cold spring; widely described by other reviewers simply as strongly salty and slick. · 2 visitors, Jan 2026 – May 2026
- Source temperature: One long-time reviewer records source temperature as 13.8C on one visit and 10.8C on another, consistent with a cold mineral spring that must be heated. · 2 visitors, Jan 2026 – May 2026
- pH: The spring's pH is measured at 6.3, in the mid-6 range. · 2 visitors, Jan 2026
- Free-flowing (kakenagashi): Widely called source-fed kakenagashi by casual visitors, but one very detailed technical review notes no visible overflow and suspects the water is actually heated and possibly diluted rather than true kakenagashi. · 5 visitors, May 2025 – Aug 2026
- Heated: The cold source spring is heated before entering the tubs; one reviewer suspects added water too, though another explicitly says no water is added. · 3 visitors, Jan 2026 – May 2026
- Full spring description: sodium chloride-bicarbonate cold mineral spring (carbonated)
Practical
What you need
Lockers
✓ FreeConfirmed by recent visitor reports
Payment
✕ Cash onlyPayment is cash only.Reported by two visitors
Hair dryer
✓ YesReported by two visitors
Facilities
Rest area
✕ NoReported by two visitors
Restaurant
✓ YesConfirmed by recent visitor reports
Lodging
✕ NoReported by two visitors
How we know this
- Lockers: Free valuables lockers are provided. · 4 visitors, May 2026 – Aug 2026
- Payment: Payment is cash only. · 2 visitors, Jan 2026
- Hair dryer: Hair dryers are available in the changing room. · 2 visitors, Jan 2026 – Aug 2026
- Rest area: There is no dedicated rest area outside of chairs by the bath entrance or the dining room (which is only accessible when ordering food). · 2 visitors, Apr 2026
- Restaurant: A well-regarded restaurant (known for grilled offal/motsu and udon) operates alongside the bath. · 6 visitors, Jan 2026 – Aug 2026
- Lodging: Signage suggests it once offered lodging ('mountain inn'), but reviewers confirm it no longer does. · 2 visitors, May 2026
Timing
When to go
Quietest Friday around 19:00. Busiest Sunday around 12:00.
| 8A | 9A | 10A | 11A | 12P | 13P | 14P | 15P | 16P | 17P | 18P | 19P | 20P | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| MO | |||||||||||||
| TU | |||||||||||||
| WE | |||||||||||||
| TH | |||||||||||||
| FR | |||||||||||||
| SA | |||||||||||||
| SU |
Quiet Busy
Based on Google visit patterns, not a forecast.
Weekly hours
| Day | Hours |
|---|---|
| Monday | 11:00–20:00 |
| Tuesday | 11:00–20:00 |
| Wednesday | 11:00–20:00 |
| Thursday | Closed |
| Friday | 11:00–20:00 |
| Saturday | 11:00–20:00 |
| Sunday | 11:00–20:00 |
Closed Thursdays, 2nd Friday.
Getting there
How to get there
Nearest station
Yokokawa · JR East9.9 km in a straight line; bus or taxi from the station
Address
12809-1 Nishinomaki, Shimonita, Kanra District, Gunma 370-2627From the facility's listing
Show a driver
八千代温泉 芹の湯The name in Japanese, for a taxi or at the counter
Phone
+81274-84-3812Japanese-speaking. For tattoos or private baths a call is the only sure answer
Website
serinoyu.comOfficial, in Japanese
The map loads only when you ask for it and connects your browser to Google.
Nearby
Other baths close by
Myōgi Fureai Plaza / Myōgi Onsen Hot Spring ‘Momiji no Yu’
3.9★ · 9.9 km · Tomioka
✓Day useTattoos ?✓Outdoor bath✓Sauna
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Questions
Common questions
Can I visit Yachiyo Onsen Seri-no-Yu without staying overnight?
The inn used to offer lodging but is now day-use only.
How much does Yachiyo Onsen Seri-no-Yu cost?
Current adult admission is consistently 800 yen (it was 500 yen in 2022 and 700 yen in 2023 per one long-time reviewer's history).
Is the water free-flowing spring water?
Widely called source-fed kakenagashi by casual visitors, but one very detailed technical review notes no visible overflow and suspects the water is actually heated and possibly diluted rather than true kakenagashi.
