Yamagata · Zao Onsen
Zao Onsen Kamiyu Public Bath
蔵王温泉 上湯共同浴場
A log-cabin-style communal bath at the top of Takayu-dōri. Zao's three public baths (Kamiyu, Shimoyu, Kawarayu) all cost ¥200, paid into an honesty box. No washing stations — just rinse and sink into the strongly acidic milky sulfur water.
- Price (adult)
- ¥300
- Hours
- 06:00–22:00
- Closed
- Open daily (cleaning periods)
- Access
- 5 min walk from Zao Onsen bus terminal
- Water type
- Acidic spring
- Tattoos
- Ask ahead
- Admission
- Adults ¥300 / children ¥100 (up from ¥200). Unattended — drop coins in the red box at the entrance (no change). Guests at Zao inns are often given free tickets for the communal baths
- Baths
- Highest of Zao’s three communal baths (Kami-yu, Shimo-yu, Kawara-yu), at the top of Takayu-dori below the steps of Sugawa Onsen Shrine. One wooden indoor tub per gender (full with 4–5 people); no washing area, showers or lockers. Free foot bath alongside. Site of Zao’s oldest communal bath
- Water
- Acidic sulfur-aluminium sulfate-chloride spring (source: Oyu No. 1), pH ~1.8, free-flowing. Hot, sour-bitter and strongly acidic. Said to have opened around AD 110 — 1,900 years, Yamagata’s oldest hot spring
- Three-bath tour
- Kami-yu (pH 1.8, mildest) → Shimo-yu (pH 1.7, tingly) → Kawara-yu (pH 1.45, water welling up through the floor), each 3–5 min apart. All ¥300, unattended, 6–22
- Phone
- 023-694-9328
- Official site
- zao-spa.or.jp ↗
- Open in Google Maps
- Google Maps ↗
Essentials
Stay in this onsen town
Compare and book stays in Zao Onsen. Day bathing itself needs no booking.
Opens partner booking site (affiliate)
Why go
- Strongly acidic sulfur water for ¥200
- Unstaffed, 6 am to 10 pm
- Hop all three public baths
¥300, unattended, one wooden tub: the purest form of a 1,900-year-old spring
Zao Onsen, said to have opened around AD 110, is Yamagata’s oldest spring, and within the village are three unattended communal baths run by residents: Kami-yu, Shimo-yu and Kawara-yu. Kami-yu (“upper bath”) is the highest, at the top of the Takayu-dori slope lined with shops and old inns, below the steps of Sugawa Onsen Shrine, on the site of Zao’s oldest bathhouse. There is nothing but one wooden tub and a changing space: drop ¥300 in the red box, rinse, and sink in. The water, strongly acidic at around pH 1.8, overflows hot, and its sour-bitter taste and heavy sulfur scent are the most direct introduction to “Zao’s water”. Open daily 6:00–22:00 even in winter when the big rotenburo is closed — a ¥300 luxury after skiing.
Tips & cautions
- Unattended: bring three ¥100 coins, no change. No lockers — leave valuables behind. Bring a towel.
- No washing area or showers, no soap. Strongly acidic: remove jewellery, protect your eyes, dry off well (it damages clothes).
- Very hot — a little cold water is acceptable, but keep it minimal for the next bather. Full at 4–5 people; if busy, try the other two.
- It is the locals’ daily bath — give residents priority in the morning and after dinner.
- Walking the three baths plus the big rotenburo (green season) is the classic Zao day. A combined ticket for four day-use facilities appeared in July 2026.
Getting there
Yamako bus ~40 min from JR Yamagata Station to the Zao Onsen bus terminal, then ~7 min on foot up Takayu-dori to the top (Zao Onsen 45-1). ~35 min from Yamagata-Zao IC. No dedicated parking — use the village’s public car parks.
Before you go
- No official tattoo policy is published — ask at reception.
- As a communal bath there is no soap or shampoo — bring your own or buy at the shop.
- Strongly acidic water — rinse off afterwards, avoid long soaks, and remove silver jewellery.
- The water runs hot (43–45°C). Don't add cold water; take short repeated dips instead.
- Payment is usually by ticket machine in cash — bring coins.
Features
Price
Mood & scenery
✔ Verified operating: 2026-10 Operating status and rates cross-checked against the official site and onsen guides (full source notes in Japanese on the JA page)
Prices and hours change. Check official sources before visiting.
More in this area
Zao Onsen Dai-Rotenburo
A terraced open-air bath along a mountain stream that holds 200 people, with bluish-white strongly acidic sulfur water. Open late April to late November only; closed in winter. Summer starlight sessions at night.
Shirogane-yu (Ginzan communal bath)
A Kengo Kuma-designed communal bath at the entrance to Ginzan's Taishō-era street. Hot water with drifting mineral flakes for ¥500. The one place day visitors can bathe in Ginzan's water — reception closes at 3:30 pm.
Ginzan Onsen Ginzansō (Day Bath)
The large ryokan at the entrance to Ginzan. Indoor, open-air and lie-down outdoor baths — far roomier than Shirogane-yu. Day use 11:30 am–2 pm (last 1:30), ¥1,500, closed Thursdays; day bathing has been suspended and resumed repeatedly, so check the website. Cash only.
