Day-use bath · Open
Nibukawa Seseragi Koryukan (Imabari City)
- Day-use bathing
- Yes
- Fee
- Unconfirmedno check date
- Hours
- Unconfirmedchecked 2026-10-09
Photo information
Save to passport
Official classification
Spring type (therapeutic classes)
Official spring-type name (as recorded)Simple hot spring (alkaline, with a high radon content)
- Source temperature
- 22°C
- pH
- Unconfirmed
- Flow rate
- Unconfirmed
- Radon
- Present
Appearance & feel
Water colour · Feel
Silky / slippery
Colour and feel are listed only where a source states them. They vary by day and by bath.
What makes it special
In the hills behind Imabari, radon-bearing alkaline water rises from a granite gorge: one of the 'three baths of Iyo' alongside Dogo and Hondani.
Why?
Wikipedia describes Nibukawa as a simple spring rich in radon, emerging from cracks in the granodiorite of the Nibukawa Gorge, and traditionally counted with Dogo and Hondani as the 'three baths of Iyo'.[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.
Ryokan (inn) · Status unconfirmed
Kairakuso
- Day-use bathing
- Unconfirmed
- Fee
- Unconfirmedno check date
- Hours
- Unconfirmedchecked 2026-10-09
Getting there
Reachable by public transport
From Imabari Station on the JR Yosan Line, about 30 minutes by Setouchi Bus towards Nibukawa.
- Getting there
- Imabari Station · 30
- Checked
- 2026-10-09
About the water
Nibukawa's water is an alkaline simple spring known for a silky feel on the skin. The source is only 22 °C, so it is heated for bathing. Wikipedia notes a high radon content, but the measured value and unit from an analysis certificate were not available, so we record only that radon is present (whether it meets the radioactive-spring threshold is unconfirmed). It is called a 'beauty bath'; we make no claims about effects.
| Source | Source temperature | pH | Radon | Checked |
|---|---|---|---|---|
| Nibukawa source | 22 | Unconfirmed | Unconfirmed | no check date |
Three things not to miss
Photo information
Nibukawa Seseragi Koryukan
At the mouth of the Nibukawa Gorge, Tamagawa-cho A city-owned day-bath facility run by a contracted operator, with a main bath, open-air bath and sauna. Fees and hours could not be read from official pages.
The one public way to try Nibukawa's water without staying overnight.[2][1]
Photo information
Nibukawa Gorge
Beyond the inns A gorge cut by the river through granodiorite; the spring issues from cracks in this rock.
You can see where the radon comes from: a granite valley. Known for autumn colour.[1]
Traces of a domain bathing resort
The village In the Edo period this was the Imabari domain's bathing resort. Hard to reach, it declined and revived more than once; the road built in 1952 brought the present village. Five inns (Wikipedia).
The quiet of a mountain cure resort, in contrast to Dogo's bustle.[1]
The story
The three baths of Iyo
In the old province of Iyo, today's Ehime, Dogo, Hondani and Nibukawa were known as the 'three baths'. Nibukawa served the Imabari domain as a cure resort in the Edo period, but poor mountain roads meant repeated decline and revival. A road built in 1952 allowed redevelopment, and today it is a small resort of five inns.[1]
Granite and radon
The water seeps from cracks in the granodiorite of the gorge. Granitic rock can contain uranium and thorium, whose decay yields radon that dissolves into groundwater, which is why Nibukawa's water is said to carry radon. We could not, however, obtain the measured figure from a published analysis. The source is 22 °C and is heated for bathing.[1]
After Dogo
From Dogo in Matsuyama, Imabari is about 40 minutes by limited express, and Nibukawa about 30 minutes further by bus. Cyclists finishing the Shimanami Kaido use it to wash off the ride. The city's Seseragi Koryukan takes day visitors, so you need not stay overnight to bathe.[1][2]
Going solo
Solo stay unconfirmedUnconfirmed
Weekend / peak restrictionsUnconfirmed
Where to eat dinnerFew eateries in the village; eat in Imabari (yakibuta-tamago-meshi pork and egg rice is the local dish)
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.
Nov — Autumn colour in the Nibukawa Gorge
Apr · May — Fresh green in the gorge; a good season to combine with cycling the Shimanami Kaido
Food, culture & experiences
Nibukawa Gorge
Granodiorite gorge known for autumn leaves[1]
Walkable from the village (time not confirmed)Cycling the Shimanami Kaido
Imabari is the Shikoku end of the island-hopping cycle route; a bath after the ride[1]
About 30 minutes by bus from central ImabariKokubunji temple (No. 59 on the Shikoku pilgrimage)
Founded 741; 22–30 minutes by Setouchi Bus from Imabari Station[3]
In Imabari, on a different bus routeEditors' guide
A natural second bath after Dogo. Take the bus from Imabari Station to Seseragi Koryukan for the heated, silky water and its open-air bath; confirm fees and hours with the facility before you go. Walk up the gorge if time allows, best in November for the leaves. If staying, ask the inn about solo rates.
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
- Fees, hours and closed days at Seseragi Koryukan could not be read from official pages; unconfirmed
- Radon value and unit unconfirmed (no analysis certificate found online)
- Inn operating status and solo stays unconfirmed; one hotel is reported closed but this could not be verified officially
- Bus frequency and fare not confirmed
Sources
- 鈍川温泉 - Wikipedia(日本語版)Wikipedia · 2026-10-09
- 今治市鈍川せせらぎ交流館 指定管理モニタリング結果(令和6年度)今治市 · 2026-10-09
- 今治市 観光情報今治市 · 2026-10-09
Register sources
- 鈍川温泉 - Wikipedia(日本語版)Wikipedia · CC BY-SA 4.0 · 2026-10-09
- Wikidata Q11648329Wikidata · CC0 · 2026-10-09
Data status
Name & locationPublishedCoordinatesPublishedSpring typePublishedPhotosPublishedFacilitiesPublishedVisiting info (dated)PublishedEditorial articlePublished
Updated 2026-10-09
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