Public bathhouse · Open
Kawayu Public Bath Yukichi
- Day-use bathing
- Yes
- Fee
- ¥500checked 2026-10-09
- Hours
- 11:00–19:00checked 2026-10-09
Photo information
Hokkaido · Onsen area
Kawayu Onsen
かわゆおんせん · 川湯温泉
Hokkaido · 弟子屈町
Status unconfirmed100 Onsen to Know Japan — No. 2
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Official classification
Spring type (therapeutic classes)
Official spring-type name (as recorded)Acidic, sulfur- and iron(II)-bearing sodium sulfate-chloride spring (hydrogen-sulfide type)
- Source temperature
- 35–65.5°C
- pH
- Unconfirmed
- Flow rate
- Unconfirmed
- Radon
- Unconfirmed
Appearance & feel
Water colour · Feel
Yunohana (mineral flakes) · Yes
Colour and feel are listed only where a source states them. They vary by day and by bath.
What makes it special
Water acidic enough to corrode a nail runs as an open river through the middle of town.
Why?
Kawayu's strongly acidic sulfur water is said to sting eyes and cuts and to corrode metal, so bathers take off their watches. A hot thermal river runs through the town, and because the acid ruins recirculation equipment every bath in Kawayu is free-flowing from the source.[1]
Facilities in this area
Facilities come from the register (Wikipedia, OpenStreetMap, official sites). Those marked "natural spring unconfirmed" are listed on the basis of their name only.
Hotel · Open
Kawayu Kanko Hotel
- Day-use bathing
- Yes
- Fee
- ¥800checked 2026-10-09
- Hours
- 13:00–21:00checked 2026-10-09
Foot bath · Open
Kawayu Park footbath
- Day-use bathing
- Yes
- Fee
- ¥0checked 2026-10-09
- Hours
- Unconfirmedchecked 2026-10-09
Getting there
Reachable by public transport
From Kawayu-Onsen Station on the JR Senmo Line, an Akan Bus takes about 10 minutes to the Kawayu bus office in town; the station itself has a footbath. Kushiro, Memanbetsu and Nakashibetsu airports are each about an hour away by car.
- Getting there
- Kawayu-Onsen Station · 10
- Checked
- 2026-10-09
About the water
Kawayu's water is a strongly acidic sulfur spring created by the volcano Mt Io. It stings eyes and cuts and corrodes metal, so take off watches and rings. Because the acid destroys recirculation and chlorination equipment, every bath in Kawayu runs straight from the source. Flakes of yunohana (mineral deposits) settle in the tubs and the water leaves skin feeling squeaky. The tourism association calls it a beauty bath; people with sensitive skin should keep soaks short and rinse afterwards.
| Source | Source temperature | pH | Radon | Checked |
|---|---|---|---|---|
| Kawayu spring group | Unconfirmed | Unconfirmed | Unconfirmed | no check date |
Three things not to miss
Photo information
The hot river through town
Centre of town around Kawayu Park Hot spring water runs through town as an open stream, wrapping the streets in steam and the smell of sulfur. A free footbath sits in the riverside park, and a rock-terrace steam area opened in October 2024.
You feel the volume and the acidity before you ever enter a bath.[1][2]
Yukichi public bathhouse
Kawayu-onsen 3-chome, in the town centre A communal bathhouse renovated in September 2024; free-flowing source water for 500 yen.
The cheapest, most honest way to meet Kawayu's acidic water.[3]
Photo information
Mt Io (Atosanupuri)
About 2.5 km / 1 hour on foot from town along the Tsutsujigahara nature trail A 508 m active volcano with reportedly more than 1,000 fumaroles you can walk right up to. Its heat is what feeds Kawayu's springs.
See the volcano that makes the water, on the same day you bathe in it.[4]
The story
Seseki-pet, the hot river
The name Kawayu translates the Ainu 'seseki-pet', hot river. The word order was flipped so as not to confuse it with the older Yunokawa Onsen near Hakodate. The first inn of 1886 turned into a gambling den and was shut down; a Russian-style inn built in 1904 is considered the true start of the resort.[1]
The national park and a film
The Senmo rail line opened in 1930 and Akan National Park in 1934, and visitors multiplied. After a great fire in 1948, the 1953 film 'Kimi no Na wa' was shot around Lake Kussharo and tourists poured in again; at the peak in fiscal 1991 the town hosted 734,000 overnight guests. The figure fell to 91,000 in 2020 during the pandemic, and the town is now being rebuilt.[1]
Acid made the rule
Kawayu's water is so acidic that it eats recirculation pumps and chlorination gear. Every bath in town therefore runs straight from the source, and the resort has issued a formal 'free-flowing source' declaration; one hotel's tubs are just 35 m from the spring. Acid and sulfur corrode metal, so watches and jewellery stay in the changing room.[1][5]
Going solo
Easy for solo travellersUnconfirmed
Weekend / peak restrictionsUnconfirmed
Where to eat dinnerTwenty-odd hotels, restaurants and shops in town
Private bathUnconfirmed
checked 2026-10-09
Through the year
Recommended months
JanFebMarAprMayJunJulAugSepOctNovDec
Months open
JanFebMarAprMayJunJulAugSepOctNovDec
"Recommended" and "open" are recorded separately. Check the season for seasonal springs.
Jan · Feb — Deep winter: steam and snow in the streets, and diamond dust on clear cold mornings
Jun · Jul · Aug · Sep · Oct — Sea-of-clouds season at Lakes Mashu and Kussharo (Jun–Oct); trekking on Mt Io
Jul — Steam beer garden in late July
Food, culture & experiences
Mt Io (Atosanupuri)
Walk from the car park right up to the fumaroles. Parking 500 yen per car, shared ticket with Mashu Lake Observatory 1[4]
About 1 hour on foot (2.5 km) or 5 min by car from townKawayu Visitor Center
Ministry of the Environment centre; free entry, 8:00–17:00 Apr–Oct and 9:00–16:00 Nov–Mar, closed Wednesdays except in high summer. Café and snowshoe rental[7]
A few minutes' walk in townTaiho Sumo Museum
Museum of the 48th yokozuna Taiho, who grew up in Kawayu[1]
In townEditors' guide
Arrive by train and test the water in the station footbath. Take the bus into town, walk the steaming river and its free footbath, then bathe at Yukichi. With time to spare, hike the trail to Mt Io and read up on the volcano at the Visitor Center on the way back. In winter the snowbound station footbath steals the show.
The "editors' guide" above is written by the editors from sources; it is not a visitor's opinion.
Photo gallery
Visitor reviews
No reviews yet. While the review platform is being prepared, we do not display fictional reviews or ratings.
Review posting is in preparation, with visit date, facility, comments on water, scenery and access, photos, language and reporting.
Onsen areas nearby
Unconfirmed & notes
- Measured pH and individual source temperatures not confirmed from official pages (Wikipedia: strongly acidic, 35–65.5°C)
- Akan Bus frequency and fare not confirmed
- Footbath hours and winter condition not confirmed
Sources
- 川湯温泉 (北海道) - Wikipedia(日本語版)Wikipedia · 2026-10-09
- 川湯温泉(北海道)〜日本最大のカルデラから生まれる名湯摩周湖観光協会 · 2026-10-09
- 川湯公衆浴場 湯吉摩周湖観光協会 · 2026-10-09
- 硫黄山(アトサヌプリ)摩周湖観光協会 · 2026-10-09
- 川湯観光ホテル摩周湖観光協会 · 2026-10-09
- 弟子屈町へのアクセス摩周湖観光協会 · 2026-10-09
- 川湯ビジターセンター自然公園財団(環境省施設) · 2026-10-09
Register sources
- 川湯温泉 (北海道) - Wikipedia(日本語版)Wikipedia · CC BY-SA 4.0 · 2026-10-09
- Wikidata Q11478935Wikidata · CC0 · 2026-10-09
Data status
Name & locationPublishedCoordinatesPublishedSpring typePublishedPhotosPublishedFacilitiesPublishedVisiting info (dated)PublishedEditorial articlePublished
Updated 2026-10-09
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