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Shirane Onsen - Large Open Air Bath
3.9★ · 534 Google ratings · Katashina, Gunma · 白根温泉 大露天風呂薬師之湯
✓ Natural hot-spring water✓ Free-flowing source water✓ Outdoor bath✓ Rest area
Before you go
Can you bathe here?
Price
¥1,000Consistently 1000 yen per adult; several reviewers feel this is high for a small roadside facility compared to nearby alternatives.stated by 8 visitors · Sep 2025 – Aug 2026
Hours
10:00–17:30 · closed Wednesdayfrom the facility listing
Tattoos
Not known · call aheadno policy stated in the 35 recent reviews we read
Watch out
Outdoor bath
Large outdoor baths (split into two sections) are the facility's signature feature; multiple reviewers also note slippery moss on the floor and insects in the water.
stated by 8 visitors · Sep 2025 – Aug 2026Payment
Cash only is accepted, and one reviewer warns large bills may be refused for lack of change.
stated by 2 visitors · Mar 2026The bath
What you’ll find
A roadside day-use bath near Nikko-Shirane popular with skiers and hikers, with one indoor and two large kakenagashi outdoor baths (no chlorination or recirculation) around 41-42C, heated changing-room floors, and a lounge, though several reviewers report a slippery mossy floor and bugs in the outdoor bath, and the soba restaurant several reviews mention no longer seems to be open.
Outdoor bath
✓ YesLarge outdoor baths (split into two sections) are the facility's signature feature; multiple reviewers also note slippery moss on the floor and insects in the water.stated by 8 visitors · Sep 2025 – Aug 2026
Indoor baths
1One indoor bath alongside the two outdoor baths.stated by 2 visitors · Nov 2025 – May 2026
Outdoor baths
2Two separate outdoor bath sections.stated by 3 visitors · Nov 2025 – May 2026
View
ForestThe outdoor bath is surrounded by maple trees, especially scenic during autumn foliage.stated by 3 visitors · Apr 2026 – Nov 2025
Rest area
✓ YesA dim, cozy lounge with free massage chairs, blankets, and free tea; one reviewer, however, found the rest area unwelcoming.stated by 4 visitors · Oct 2025 – Mar 2026
Restaurant
NoA soba restaurant is mentioned in older reviews, but two more recent visitors found it (and a foot bath and boiled-egg stand) no longer operating.stated by 2 visitors · Oct 2025 – Dec 2025
The water
Free-flowing (kakenagashi)
✓ YesConsistently and heavily documented as true kakenagashi with visible overflow, not recirculated.stated by 10 visitors · Sep 2025 – Jul 2026
Bath temperature
42°CThe baths run a consistent 41-42C.stated by 4 visitors · Jan 2026 – Jul 2026
Practical
What to bring
Payment
Cash onlyCash only is accepted, and one reviewer warns large bills may be refused for lack of change.stated by 2 visitors · Mar 2026
Lockers
✓ FreeFree valuables lockers with keys are provided in the changing room.stated by 2 visitors · Apr 2026 – Dec 2025
Hair dryer
✓ YesFree hair dryers are provided.stated by 2 visitors · Oct 2025 – Dec 2025
Guide
What visitors add
Water handling
Source kakenagashi is the facility's strongest confirmed trait — about 14 reviewers state it; one notes 'overflow' lettering at the rotenburo, one says all tubs are kakenagashi, one says no circulation, and one says no disinfection, with abundant flow mentioned repeatedly.
stated by 14 visitors · Sep 2025 – Jul 2026Price
Admission is 1,000 yen (12 reviewers, Sep 2025-Aug 2026) with no time limit per one reviewer; a name-printed towel with toothbrush sells for 200 yen (1 reviewer). Seven reviewers independently call the price high for what is offered.
stated by 12 visitors · Sep 2025 – Aug 2026Outdoor bath & sauna
Layout is one large indoor bath plus two outdoor tubs (6 reviewers) — one outdoor tub hot and one milder, the milder one with an utase-yu waterfall spout per one reviewer. No reviewer mentions a sauna. Whether the 'giant rotenburo' lives up to its name is contested: 6 reviewers describe it as genuinely large or huge, while 4 say it is just an ordinary-sized rotenburo that undersells the billing.
stated by 10 visitors · Oct 2025 – Jul 2026The water
Weak-alkaline simple hot spring (4 reviewers), colorless and transparent (4 reviewers), around 41-42°C (4 reviewers, several finding it slightly hot). Reviewers split on smell: two detect a faint sulfur scent while three say it is odorless or sulfur-free (one recommending it for people who dislike sulfur).
stated by 9 visitors · Oct 2025 – Jul 2026Towels, soap & lockers
Shampoo etc. and hair dryers are provided (2 reviewers); the changing-room lockers are open shelves, with free keyed valuables lockers in the changing room (2 reviewers). A standout comfort: the changing-room floor is heated by the onsen itself — 6 reviewers mention the warm floor.
stated by 8 visitors · Oct 2025 – Apr 2026Outdoor bath & sauna
Three reviewers warn the rotenburo floor is slippery (moss or slime — one flags danger for children and the elderly), and three separately report leaves, insects or insect debris in the open-air water; one was bitten by a horsefly in July.
stated by 6 visitors · Sep 2025 – Jul 2026Timing
When to go
Quietest Thursday around 10:00; busiest Sunday around 15:00. Measured by Google over past visits, not a forecast.
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Quiet Busy
| Day | Hours |
|---|---|
| Monday | 10:00–17:30 |
| Tuesday | 10:00–17:30 |
| Wednesday | Closed |
| Thursday | 10:00–17:30 |
| Friday | 10:00–17:30 |
| Saturday | 10:00–17:30 |
| Sunday | 10:00–17:30 |
Closed Wednesday.
Practical
Plan your visit
📍 4667 Higashiogawa, Katashina, Tone District, Gunma 378-0414
🚃 Sori station, 26.0 km
📞 +81278-58-4126
📋 Show at the counter: 白根温泉 大露天風呂薬師之湯
Nearby
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