Japan Onsen Atlas温泉アトラス
Iya Onsen open-air bath
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As6022014 Public domain View original page

Shikoku · Onsen area

Iya Onsen

いやおんせん · 祖谷温泉

Tokushima · 三好市

Open100 Onsen to Know Japan — No. 83
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Official classification

Spring type (therapeutic classes)

Sulfur springSimple hot spring

Official spring-type name (as recorded)Alkaline simple sulfur hot spring

Source temperature
38°C
pH
9.1
Flow rate
Unconfirmed
Radon
Unconfirmed

Appearance & feel

Water colour · Feel

Silky / slipperybubbles

Colour and feel are listed only where a source states them. They vary by day and by bath.

What makes it special

A cable car drops you about 170 metres down a 42-degree cliff in five minutes, to a riverside bath where the source runs in at 38 °C.
Why?

Hotel Iya Onsen's official site describes a 5-minute cable-car descent down a 42-degree cliff to an open-air bath 170 m below, a source temperature of around 38 °C and flow-through bathing.[1][2]

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

Hotel Iya Onsen

Day-use bathing
Yes
Fee
¥2,000checked 2026-10-09
Hours
7:30–17:00checked 2026-10-09
Official site
Baths4
TypeGenderSourceBath temperatureFree-flowingAdded waterHeatedRecirculatedDisinfected
Open-air bathSeparateIya source38°CYes[3][2]Unconfirmed[3][2]No[3][2]Unconfirmed[3][2]Unconfirmed[3][2]
Open-air bathSeparateIya sourceUnconfirmedYes[3]Unconfirmed[3]Unconfirmed[3]Unconfirmed[3]Unconfirmed[3]
Indoor bathSeparateIya sourceUnconfirmedUnconfirmed[2]Unconfirmed[2]Unconfirmed[2]Unconfirmed[2]Unconfirmed[2]
Private bathUnconfirmedIya sourceUnconfirmedUnconfirmed[3]Unconfirmed[3]Unconfirmed[3]Unconfirmed[3]Unconfirmed[3]

Getting there

Reachable by public transport

From Awa-Ikeda on the JR Dosan Line, about 50 minutes by Shikoku Kotsu bus (Wikipedia). Shikoku Kotsu's Iyakei line runs Kazurabashi Yumebutai to Hotel Iya Onsen in about 14 minutes, three times a day (Oct 2026 timetable; no service on 1 Jan). Overnight guests can book the hotel shuttle from JR Oboke Station (one a day, 15:10, about 30 minutes, reserve by the day before).

Getting there
Awa-Ikeda Station · 50
Getting there
Three buses a day on the Iyakei line between Kazurabashi Yumebutai and the hotel; frequency from Awa-Ikeda not confirmed
Through the year
Snow and ice possible in winter (details not confirmed)
Checked
2026-10-09
Show on mapOpen in Google MapsOfficial site

About the water

Iya's water is an alkaline (pH 9.1, per Wikipedia) simple sulfur spring that the hotel describes as slippery and velvety. At around 38 °C it is close to body temperature, and the riverside bath takes it unheated, so this is a long, tepid soak rather than a hot one. Fine bubbles collect on the skin, which the hotel calls 'silk bubbles'. It is marketed as a beauty bath; we make no claims about effects.

SourceSource temperaturepHRadonChecked
Iya Onsen source389.1Unconfirmedno check date

Three things not to miss

Iya Onsen open-air bath
Photo information
As6022014 Public domain View original page
01

The cable-car bath, Kinpo-muso-no-yu

At the foot of the gorge below the hotel, beside the Iya River A private cable car beside the hotel entrance takes about 5 minutes to descend 170 m. The source flows straight through, and the hotel describes 'silky bubbles' wrapping the skin. Day visitors: 7:30–17:00 (reception until 16:00), 2,000 yen including the cable car and the upper panoramic bath. Closed Wednesdays.

Rather than pump tepid water up and heat it, the hotel carries the bather down to where it emerges. The view up the gorge from the tub exists nowhere else.[2][3]

Iya Onsen cable car
Photo information
ブルーノ・プラス CC BY-SA 4.0 View original page
02

The new cable car

Hotel to riverside bath The car was replaced in 2023 (per the Commons photographer's note). You descend watching the gorge through the windows.

The ride is part of the ritual of the bath.[1]

03

Panoramic bath Unyu-tenku-no-yu

In the main building An indoor bath looking down into the gorge from the clifftop, included in the day fee. Overnight guests may use it 11:30 to 10:00 the next morning.

Compare the same water tepid at the river and warmer on the clifftop.[3][2]

The story

The lone inn of a hidden valley

The Iya Gorge, a deep valley on a tributary of the Yoshino River, is counted among Japan's 'three great hidden regions' and keeps legends of Heike clan refugees. Iya Onsen is a single inn on the clifftop; Wikipedia lists one lodging. Because the spring rises at the river's edge far below, the inn built a cable car to carry bathers down to it.[4][2]

Not heating 38 degrees

The source is around 38 °C. Where most inns would heat it to 42, Iya Onsen places its tub at the point of emergence and lets the water run through as it is. The alkaline sulfur water feels slippery and leaves fine bubbles on the skin, which the inn calls 'silk bubbles'. In 2023 the cable car itself was replaced.[2][3]

Getting there is the journey

By public transport, buses from Awa-Ikeda take about 50 minutes. The Iyakei line (Oct 2026 timetable) links the Kazurabashi bus terminal and the hotel three times a day each way, and overnight guests can book the 15:10 shuttle from JR Oboke. By car, Route 32 follows the river through the gorge, narrow and winding.[4][5][6]

Going solo

Hard to stay aloneUnconfirmed
Weekend / peak restrictionsUnconfirmed
Where to eat dinnerAlmost no restaurants nearby; the hotel serves Iya-style meals of mountain vegetables and river fish
Private bathYes

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.

Oct · Nov — Autumn colour in the gorge, seen from the riverside bath

Apr · May — Fresh green; the tepid bath is at its most comfortable

Dec · Jan · Feb — At 38 °C the open-air bath can feel cold in winter; pair it with the indoor panoramic bath

Food, culture & experiences

Available / bookable

Iya Kazurabashi vine bridge

A suspension bridge woven from kiwi-family vines; the Iyakei bus starts here[5]

About 14 minutes by bus
Available / bookable

Hi-no-ji bend and the Peeing Boy statue

Viewpoints on Route 32 above the gorge, on the Iyakei bus route[5]

A few minutes by car from the hotel
Available / bookable

Oboke and Koboke gorges

Gorges on the Yoshino River with sightseeing boats; JR Oboke is the gateway station[6]

About 30 minutes from Oboke Station by hotel shuttle
Available / bookable

Iya soba and dekomawashi skewers

Local dishes: thick buckwheat noodles and skewers of taro, tofu and konnyaku grilled with miso[7]

At eateries around the vine bridge

Editors' guide

Day reception closes at 16:00, so see Oboke or the vine bridge in the morning and arrive early afternoon. Ride down first and give the 38 °C bath at least half an hour to feel the bubbles form, then warm up in the panoramic bath upstairs. The open-air bath feels cold in winter; spring to autumn is its season. There are no restaurants nearby, so eat at the hotel or near the bridge.

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

  • Solo-stay terms not confirmed
  • Bus frequency and fare from Awa-Ikeda, and winter road restrictions, not confirmed
  • pH and temperature from Wikipedia (9.1, 38 °C); analysis date not confirmed
  • Tattoo policy, towels and dilution notice not confirmed

Sources

  1. 和の宿 ホテル祖谷温泉 公式サイトホテル祖谷温泉 · 2026-10-09
  2. ホテル祖谷温泉 温泉のご案内ホテル祖谷温泉 · 2026-10-09
  3. ホテル祖谷温泉 露天風呂・日帰り入浴ホテル祖谷温泉 · 2026-10-09
  4. 祖谷温泉 - Wikipedia(日本語版)Wikipedia · 2026-10-09
  5. 四国交通 路線バス 時刻表・運賃表(祖谷渓線 2026年10月1日改正)四国交通 · 2026-10-09
  6. ホテル祖谷温泉 アクセスホテル祖谷温泉 · 2026-10-09
  7. ホテル祖谷温泉 ご宿泊ホテル祖谷温泉 · 2026-10-09

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Data status

Name & locationPublishedCoordinatesPublishedSpring typePublishedPhotosPublishedFacilitiesPublishedVisiting info (dated)PublishedEditorial articlePublished

Updated 2026-10-09

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