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Akayu Onsen

赤湯温泉

63°Csulfursodium-chloridecalcium-chloride
Save
45–63°CWater temp
7.2pH
¥300 (~$2)Entry fee
PublicBathing type
Check hoursLocal statusMo-Su 06:00-22:00
Opening hours

Akayu Onsen

sulfur · Tohoku

Temperature45–63°C
30°50°70°90°+

Hotter than 56% of Japan springs (n=122).

pH level7.2 — Neutral
Acidic 147 Neutral1014

More acidic than 41% of Japan springs (n=121).

Mineral profile

SulfurPrimary component
Sodium ChlorideSecondary component
Calcium ChlorideTrace component

Bar width reflects listing order, not measured concentration.

Suitability

Tattoo policy
Prohibited
Children
Allowed
Altitude
185m

At a glance

Getting there

Easy — under 1km from a station

Cost

Low

About this spring

Akayu Onsen is a historic hot spring town in Nanyo City, Yamagata Prefecture, situated along the Mogami River. The thermal waters carry a sulfurous quality and are valued for their warming effect on the body. The name Akayu, which translates as red hot water, comes from a founding legend rooted in 1093, when soldiers serving Minamoto no Yoshie reportedly bathed in the spring after sustaining wounds, and their skin turned visibly red in the water.

Highlights

Sulfurous warming springsFounded 1093, Minamoto clan legendFormer Uesugi noble retreatPost-town Mogami River setting

History

In the autumn of 1093, warriors of the Minamoto clan moved through this valley in Yamagata.

Local tradition holds that injured men among them found a reddish spring, bathed in it, and recovered with unusual speed. The reddening their skin showed in the water became the origin of the spring's name. The settlement developed over time into a post station along the Oshu Kaido, the great northern highway. During the Edo period, the Uesugi clan of the Yonezawa domain claimed Akayu as a reserved bathing ground for domain nobility. When the Meiji Restoration ended those domain privileges, the town opened itself to the general public as a resort.

Local guide

From Yamagata Station, the Yamagata Shinkansen carries you south through broad rice paddies before the landscape tightens into the rolling hills of Nanyo City. Akayu sits at the center of this small city, about forty minutes from Yamagata by local train. When you step off at the station, the town announces itself immediately with a faint sulfurous tang in the air, the kind of smell that is sharp without being unpleasant, more like struck matchheads than rotten eggs. Fourteen inns and four public bathhouses are spread across a compact grid of streets that you can cover in an easy twenty-minute walk.

The water here is a blend of sulfur, sodium chloride, and calcium chloride, a combination that makes it quite different from the single-note springs you find in alpine villages. It comes out clear, but the sulfur content gives it a slight milky quality in deeper pools, somewhere between transparent and faintly white. On your skin it feels clean and mildly astringent, and the salt content means you feel warm for a long time after you leave the tub. The temperature runs hot, and in winter the contrast between the cold night air and the steaming surface of an outdoor pool is one of the better sensations available in Tohoku.

The public bathhouse Yukotto, which opened in 2022 after the older Azuma-yu and Towa-no-yu facilities closed after fifty years of service, is the central gathering point for locals. It is a plain, functional building, not the grand architectural statement you will find at some famous onsen towns, but that is exactly the point. You buy your ticket from a machine, fold your clothes into a basket, and within two minutes you are submerged alongside Nanyo residents who clearly consider this a normal Tuesday evening. There is no performance of tradition here, just the actual thing.

Akayu also sits in the middle of one of Japan's most productive wine-growing valleys. The Mogami River basin has been growing grapes since the nineteenth century, and several wineries operate within a short drive of the bathhouses. The combination that locals propose, a long soak followed by a glass of Nanyo red wine and a plate of Yonezawa beef, is not a tourist gimmick. It is simply what people do here. If you arrive in cherry blossom season, the ryokans along the main street put on a brief, sincere show of pink that frames the steam rising from the baths in a way that feels genuinely worth seeing.

Mineral chemistry

Water character inferred from mineral type — verify on site.

Sulfur
Benefits

Sulfuric hot springs are among the most studied in balneology worldwide. The sulfur compounds, primarily hydrogen sulfide and thiosulfate, have documented antimicrobial and anti-inflammatory properties. Regular bathing is associated with relief from chronic skin conditions including eczema and psoriasis, as well as joint inflammation and muscle soreness. Sulfuric waters have been used therapeutically across Asia and Europe for centuries.

Note

The distinctive rotten-egg smell dissipates quickly after leaving the bath. Avoid if you have a sulfur allergy, very sensitive skin, or respiratory conditions. Remove silver jewellery before entering — sulfur will blacken it permanently.

Sodium Chloride (Salt)
Benefits

Sodium chloride springs, essentially natural saltwater baths, are celebrated for their warming and moisturising effects. The salt forms a thin film on the skin that slows moisture evaporation, keeping skin hydrated longer than a freshwater bath.

Note

Those with high blood pressure or heart conditions should consult a doctor before bathing, as the warming effect increases circulation. Avoid immersing open wounds.

Calcium Chloride
Benefits

Calcium chloride springs share the heat-retaining property of sodium chloride springs but with a stronger warming effect. Prized for muscle and joint relief.

Note

The strong warming effect means those with cardiovascular conditions, high blood pressure, or pregnancy should limit soak duration and consult a doctor if in doubt.

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Amenities

Towel rental
Locker / Cottage rental
Restaurant
Cafe
Parking
Wheelchair accessible
English spoken
Tattoo friendly
Private bath available
Soap provided
Hair dryer

Getting there

Take the Yamagata Shinkansen from Tokyo to Akayu Station. The journey takes about 2 hours 30 minutes. The town center and main ryokan are within walking distance of the station.

Location & nearby

Akayu Onsen, Nanyō, Yamagata

Kaminoyama-Onsen Station · 14.8 kmShinkansen
Akayu Station · 1.7 km
Nanyo-Shiyakusho Station · 1.8 km
Miyauchi Station · 3.7 km
えくぼプラザ · 0.1 km
Yamagata Airport · 44 km
Sendai Airport · 66.4 km
Ekubo Plaza Station · 0.1 km
Akayu Onsen Yokotto (Bus Stop) · 0.2 km
Akayu Onsen-guchi Station · 0.3 km

Make a day of it

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More springs in Tohoku

Sukayu Onsen
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Set deep in the Hakkoda Mountains of Aomori Prefecture, Sukayu Onsen is a historic bathhouse best known for its cavernous mixed-bathing hall, the Sen-nin-buro, which translates as the Bath of a Thousand Bathers. The waters are strongly acidic, the setting is rustic and unhurried, and winter brings extraordinary snowfall to the surrounding mountains.

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Tsuru-no-yu is the oldest of the seven inns at Nyuto, set deep in a beech forest in Akita Prefecture. The main draw is a large outdoor mixed-bathing pool fed by opaque, milky-white sulfurous water. Many regard it as the most beautiful onsen setting in Japan. People come here to put some distance between themselves and the rest of the world for a while.

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Common questions

What is the water temperature at Akayu Onsen?▾

The water temperature at Akayu Onsen ranges up to 63°C (minimum around 45°C).

Is Akayu Onsen free to visit?▾

Akayu Onsen charges an entrance fee in JPY.

Is Akayu Onsen a public or private bath?▾

Akayu Onsen is a public bathing spring.

Are tattoos allowed at Akayu Onsen?▾

No, Akayu Onsen does not permit visible tattoos.

Listing last edited: 2026-06-22