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Iseya

伊せやいせや

Lodging

Day Use

Yes
11:00–15:00
¥600

Bathing & Water

Natural onsen water

Uses natural hot spring water

Outdoor BathYes

Open-air outdoor bath

Indoor BathYes

Enclosed indoor bathing area

温火湯

Atsuhi-yu Spring

Operated by · 田辺市四村川財産区

Sulfur
+ Bicarbonate · Chloride
Color
faintly yellow
Taste
moderately faint with a metallic edge
Odor
a moderate hydrogen sulfide note

Sodium Bicarbonate-Chloride spring

pH 7.3NeutralHot source · 83°C
Composition fingerprint1.7 g/kg dissolved · Hypotonic
Na⁺91
HCO₃⁻67
Cl⁻30
CationsAnions
Sodium Na⁺
salt's cation — pairs with chloride to make the water salty.
Bicarbonate HCO₃⁻
"soda" — softens skin, leaves it smooth.
Known good for
  • Skin conditionsatopic skin, eczema
  • Circulationtired legs
  • Aches & jointsstiff shoulders
  • Sensitive-skin cautionbroken or dry skin

A sulfur-bearing sodium bicarbonate-chloride spring rising at a scalding 83 °C, placing it among Japan's hottest natural sources. It carries a moderate hydrogen sulfide note, with the white flecks of yunohana drifting in the water. Neutral in pH and soft on the skin, the bicarbonate character is rounded out by a salty edge, and a generous 178.5 mg/kg of metasilicic acid lends a smoothing touch.

Sampled at wellhead·Analyzed Apr 27, 2015·一般社団法人 和歌山県薬剤師会 医薬品・公衆衛生検査センター·Cert no. 第G1502077号

Explore the water

Programs

About

A plain toji (湯治) inn in Yunomine (湯の峰), the small hot-spring village where Kumano Kodo pilgrims washed before walking on to the shrines, and which claims to be the oldest onsen in Japan. Iseya runs its baths on undiluted source water: sulfurous, and thick with yunohana (湯の花), the pale mineral flakes that settle out of it. There are two baths, Hangan-yu (判官湯) and Hime-no-yu (姫之湯), named after Oguri Hangan and Terute-hime of the local revival legend, with a small open-air tub on one side. Fourteen rooms, and a couple of minutes on foot to Tsuboyu (つぼ湯), the tiny rock bath down in the streambed that is part of the World Heritage listing.

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1 review

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Sergey M
1 year ago

603. Iseya, Yunomine Onsen, Wakayama Visited for higaeri at 600 yen. Higaeri hours from 11:00 to 15:00. They stamp the Wakayama 88 Onsen book. The owner walked me to the onsen, pointed to which one to enter, but the curtains were for the women's side. Photo of the composition plaque from the internet. Indoor bath with clear water, large mineral fragments on the bottom, light smell from the water. Temperature around 42°C. Breathing inside is fine. Outdoor stone bath behind a solid fence. Clear water with mineral fragments on the bottom, light smell from the water. Temperature around 41.5°C. 13.06.2025

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Last updated July 29, 2026