Right Onsen › Gunma › Kusatsu
Naginoyu
3.8★ · 42 Google ratings · Kusatsu, Gunma · 凪乃湯
✓ Natural hot-spring water✓ Free-flowing source water
Before you go
Can you bathe here?
Day visitors
Local residents onlySince around 2021, review after review reports this communal bath is restricted to local town residents, with outsiders turned away.stated by 9 visitors · Jan 2021 – Sep 2025
Hours
07:30–19:00from the facility listing
Price
FreeThis is a free communal bath with no entry fee, confirmed by several reviewers.stated by 3 visitors · Oct 2018 – Sep 2025
Tattoos
Not known · call aheadno policy stated in the 35 recent reviews we read or on the facility's website
Watch out
Day visitors
Since around 2021, review after review reports this communal bath is restricted to local town residents, with outsiders turned away.
stated by 9 visitors · Jan 2021 – Sep 2025Bath temperature
Reviewers measure the water anywhere from 48C to 53C across visits; it is consistently described as too hot to enter without adding cold water.
stated by 5 visitors · Nov 2019 – Jun 2026The bath
What you’ll find
A tiny, free wooden-tub public bathhouse (kyodo-yokujo) in Kusatsu fed by the Nishinokawara source, famous for scorching, near-unbearable water temperatures, now largely restricted to local residents.
Indoor baths
1There is a single small indoor tub that fits at most a few people at once.stated by 1 visitor · Mar 2020
The water
Spring type
Acidic (colorless, Nishinokawara source)The water is a clear, strongly acidic spring, strong enough that one reviewer's skin felt dry afterward.stated by 2 visitors · Jan 2019 – Jul 2020
Bath temperature
48°CReviewers measure the water anywhere from 48C to 53C across visits; it is consistently described as too hot to enter without adding cold water.stated by 5 visitors · Nov 2019 – Jun 2026
Guide
What visitors add
The water
The water is extraordinarily hot, arguably Kusatsu's hottest bath: more than 15 distinct reviews (2018-2026) call it too hot to enter without adding cold water, with measured/estimated temperatures of 48 degrees C (2020), 50+ degrees C (2020), 51 degrees C (2024) and 53 degrees C (2026); one reviewer says it is hot enough to boil eggs and several gave up without bathing.
stated by 15 visitors · Dec 2018 – Jun 2026For foreign visitors
Access for non-residents is conflicting and time-dependent: 8 reviews from 2021-01 to 2025-09 report the bath is restricted to Kusatsu residents (several citing COVID as the reason, one noting it was locked), yet at least 4 other reviews from 2024-07 to 2026-06 describe actually entering as visitors. Two September 2025 reviews days apart contradict each other, so a visitor cannot count on being admitted.
stated by 12 visitors · Jan 2021 – Jun 2026The water
The bath uses the Sainokawara spring source: 4 reviews state this directly (one calling it the only Kusatsu public bath on that source), and 3 reviews describe strongly acidic water (colorless and clear per one; sour-tasting per another; skin left rough/dry per a third).
stated by 7 visitors · Jan 2019 – Dec 2024Price
Admission is free: 4 reviews (2018-2025) state the bath costs nothing, one identifying it as one of Kusatsu's 19 free communal baths.
stated by 4 visitors · Oct 2018 – Sep 2025For foreign visitors
Etiquette pressure on outsiders is real here: one reviewer says visitors should not bathe too openly since it is fundamentally for locals, another relays complaints that tourist manners are bad, and 2 reviewers stress you must restore the water/lights (turn off tap water, lights, re-open the source valve) before leaving.
stated by 4 visitors · Jan 2020 – Jul 2024Water handling
One reviewer explicitly describes the bath as free-flowing from the source (kakenagashi); another notes bathers can (and locals do) dilute it with tap water, and that the source valve can be shut but must be reopened when leaving.
stated by 2 visitors · Mar 2020Timing
When to go
Quietest Monday around 11:00; busiest Monday around 1:00. Measured by Google over past visits, not a forecast.
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Quiet Busy
| Day | Hours |
|---|---|
| Monday | 07:30–19:00 |
| Tuesday | 07:30–19:00 |
| Wednesday | 07:30–19:00 |
| Thursday | 07:30–19:00 |
| Friday | 07:30–19:00 |
| Saturday | 07:30–19:00 |
| Sunday | 07:30–19:00 |
Practical
Plan your visit
📍 乙４９６ Kusatsu, Agatsuma District, Gunma 377-1711
🚃 Haneo station, 8.3 km
📋 Show at the counter: 凪乃湯
Nearby
Other baths close by
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