Tamagawa Onsen

Onsen Hikyo

Prefecture

Akita

Type

Onsen · Hikyo

N/A

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Restaurant

About This Destination

A hot-spring cure town 43 km up a mountain road from Tazawako Station, built around the Obuki source: 98°C water at pH 1.2, about 9,000 liters a minute from a single vent. People lie on the steaming ground along the trail for bedrock bathing. The inn is open from late April to late November (check the closing date with the inn), and the road beyond the dam shuts to cars for the winter.

Tamagawa Onsen does not look like a resort. It is a toji town, a place where people with chronic illnesses come for a week or a month to bathe several times a day, and the guests in the halls are mostly there for that. The source is the reason: the Obuki vent pushes out 98°C water at pH 1.2, which the inn calls the most acidic in Japan, at about 9,000 liters a minute, which it calls the largest flow from one spot in the country. The water is hydrochloric acid at heart and stings any scratch on your skin. The Aomori hiba bath hall has 11 tubs, from 100 percent source water (cooled for you) down to diluted and weakly acidic ones, with separate men's and women's sides. Outside, a stone-paved nature trail of about 30 minutes loops past the Obuki and steaming vents to the spots where people lie on straw mats over the hot ground, about 40 minutes at a time. Some patches reach 40 to 50°C, so turn over now and then. The inn lends nothing for this; bring a mat, a towel for a pillow, a blanket and water. The gray hokutolite crusts here are a special natural monument and collecting them is banned.

Location

Prefecture: Akita

Address: Semboku, Akita, Japan

Nearest Station: Tazawako Station

Best time to visit: Late April to mid-October, when the bus runs six times a day; the inn closes for winter from late November to April

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Visitor Information

Credit Cards: Unknown

Official Website

Frequently Asked Questions

Can I visit Tamagawa Onsen as a day trip by bus?

Yes, while the inn is open, from late April to late November (check the closing date with the inn); on the 2026 timetable the bus runs April 16 to November 30. Take the 9:30 Ugo Kotsu bus from Tazawako Station (arrives 10:45), bathe between 10:00 and 15:00 (last entry 14:30, 1,000 yen), walk the nature trail, and catch the 14:00 or 15:55 bus back.

Can I go to Tamagawa Onsen in winter?

No. The inn and the nature trail close from late November to late April (check the closing date with the inn), and from December to late April Route 341 between Futagami-kan and Sumikawa is closed to private cars. The sister inn Shin-Tamagawa Onsen uses the same source and stays open; in the 2025/26 winter it was reachable only by the Ugo Kotsu bus from Tazawako Station, four round trips a day.

Do I need to bring anything for the bedrock bathing?

Everything. The inn rents nothing and does not allow its yukata or slippers on the rocks. Bring a straw mat (the inn says rush beats vinyl), a towel or clothes for a pillow, a blanket, light sweat clothes, a change of clothes, sneakers and a drink. Stay about 40 minutes and shift position, since some spots reach 40 to 50°C.