Tamagawa Onsen: Day-Use Hot Spring Baths & Prices

Tamagawa Onsen wells up in Shibukurozawa in Semboku City, Akita Prefecture, in the mountain bosom of Towada-Hachimantai National Park. From the source known as "Obuke," scalding water at 98 degrees erupts, and at 9,000 liters per minute the volume from a single source is the largest in Japan. It is a strongly acidic spring of pH 1.2 whose main component is hydrochloric acid, and healing guests gather here from across the country - one of Japan's foremost therapeutic waters.

Highlights

From the inn up to the valley of Jigokudani runs the stone-paved "Tamagawa Onsen Garden Nature Trail." A circuit takes about 30 minutes. Beside the path, wrapped in primeval forest of beech and Maries' fir, the source flows as a river of hot water and steam rises from fumaroles here and there. This is the place called "the birthplace of the stone sauna," and the scene of healing guests laying mats on the geothermally warmed rock and lying down is unique to Tamagawa. An indoor stone sauna unaffected by the weather is also provided inside the building.

The large bathing hall is built of Aomori hiba cypress, said to stand up well to acidity. Eleven kinds of tubs are lined up - a box steam bath, a standing bath, a lying bath, a pounding-water bath, a steam bath and more - so you can choose how to bathe according to your condition that day.

From the Obuke source, scalding water erupts with a roar amid the scent of sulfur and rising steam. The signature natural rock bath channels heat straight from the ground, and the sight of guests lying on mats is unique to Tamagawa. A walking path also lets you see hokutolite, a mineral that emits trace radiation. Hokutolite is a rare mineral found only here and at Beitou hot spring in Taiwan.

The Riverbed Where Hokutolite Sleeps

What made the name of Tamagawa Onsen known around the world is hokutolite, a mineral containing radioactive radium. It is formed when components contained in the strongly acidic hot spring water precipitate and accumulate; it consists of barium sulfate and lead sulfate and is known academically as plumbian barite. It is produced only at Beitou hot spring in Taiwan and here at Tamagawa Onsen. The "Hokutolite of Tamagawa Onsen" was designated a National Natural Monument on October 12, 1922 (Taisho 11). It is now protected as a Special Natural Monument and collecting it is prohibited.

Another characteristic of this healing retreat is that research into hot spring therapy continues here. Inside the building there is a healing consultation room staffed by a resident nurse, and bathing guidance is given even to first-time visitors. Lectures by the Tamagawa Onsen Research Society are also held in the building, where its use as a hot-spring-based health promotion facility is discussed.

Etiquette for the Natural Stone Sauna

For the natural stone sauna carried out on the rock area beside the nature trail, no equipment is lent out. You prepare everything yourself: a mat to soften the harshness of the rock face, a bath towel or clothing to serve as a pillow, a towel blanket or blanket to cover yourself, a change of clothes, and drinks. A rush-grass mat is said to suit better than a vinyl one, and a backpack is more convenient than a bag. The yukata and slippers from your guest room may not be used on the rocks.

Since the hot spots reach 40 to 50 degrees, change the direction your body faces from time to time to avoid low-temperature burns. The guideline is about 40 minutes per session, one or two times a day. Because you sweat heavily, light clothing such as sweats is best, and since the outside air is chilly morning and evening, prepare something to throw on and sneakers that are easy to walk in.

Enjoying the Seasons

From lingering spring snow to fresh greenery and autumn foliage, the high-mountain seasons unfold here. In winter some facilities close due to heavy snow, so check ahead.

Access and Basic Information

About 1 hour 20 minutes by Ugo Kotsu bus from JR Tazawako Station. Driving in from the Hachimantai Aspite Line is also popular. Note that the main Tamagawa Onsen closes for the winter, operating roughly from late April to late November, while the nearby Shin-Tamagawa Onsen operates year-round. Day bathing is offered, though hours and fees should be checked.

Practical Information

• Spring quality and indications: Acidic aluminum-iron chloride spring (hypotonic, acidic, high-temperature spring). It is said to be indicated for neuralgia, rheumatism, skin conditions and more
• Source temperature, pH and flow rate: The source "Obuke" is 98 degrees, pH 1.2, and 9,000 liters per minute. The volume from a single source is the largest in Japan
• How the water is used: The large bathing hall has 11 kinds of tubs, including 100 percent source water, 50 percent source water and weakly acidic tubs. Because the 100 percent source tub is strongly stimulating, it is adjusted to a lukewarm temperature
• Day-trip bathing: 10:00-15:00 (last admission 14:30), adults 1,000 yen, children 500 yen. Fees were revised on April 16, 2026. The day-trip rest hall is available 10:00-15:00 for 1,500 yen
• Open-air and private baths: Tamagawa Onsen has no open-air bath. The private bathing rooms are for overnight guests only, by reservation from 7:00 to 21:00. If you want an open-air bath, go to the sister facility Shin-Tamagawa Onsen
• Indoor stone sauna: For overnight guests only, by reservation, with 25 beds in total, 7:00-20:50. The usage fee is 800 yen (300 yen for members), plus 500 yen for a samue outfit and 200 yen for a bath towel. It became a paid service on October 1, 2024
• Drinking the water: The large bathing hall has facilities for drinking the water, and guests are instructed to dilute it 38 times before use
• Footbath: 8:00-17:00. Available only from April 16 to November 15
• Parking: Day-trip visitors should use the "Akita Prefectural Tamagawa Garden Parking Lot" on the left partway down the road to the inn. 8:30-16:30, 300 yen per visit. Overnight guests unload their luggage in front of the inn, after which staff direct them to parking spaces on a loop road about 2 km away
• Access: From in front of JR Tazawako Station take the Ugo Kotsu "Express Tamagawa Line" and get off at "Tamagawa Onsen," 70-80 minutes (in winter the "Express Shin-Tamagawa Line"). By car it is about 110 minutes from the Morioka IC on the Tohoku Expressway via National Route 46 and National Route 341. From Akita Airport it is 180 minutes on the "Akita Airport Liner Tamagawa-go"
• Winter road conditions: Tamagawa Onsen closes for the winter, operating roughly from late April to late November. In 2026 it reopened on April 16. On National Route 341, in the spring just after the road opens and from autumn into winter just before it closes, the stretch between Futagamikan on the Lake Tazawa side and Sumikawa on the Kazuno side is closed at night from 19:00 to 8:00. The one that stays open in winter is the sister facility Shin-Tamagawa Onsen
• Preparing for bears: On the nature trail, measures have been taken such as intensified grass cutting, the placing of repellents and sound devices, and the deployment of air horns inside the stone sauna tents, and trekking poles and bear bells are lent out free of charge. Visitors are asked to refrain from going out at night or early morning, to avoid bringing food and drink onto the trail, and to move in groups
• Barrier-free: Shin-Tamagawa Onsen is described as a barrier-free inn with handrails and floors free of steps
• Time needed and crowds: One to one and a half hours for bathing alone; allow half a day if you combine a walk on the nature trail and the stone sauna
• Other facilities: The shop is open 8:00-18:00; in the laundry the washing machines are free and the dryers are 100 yen for 40 minutes. The healing consultation room is open 8:30-16:30 by reservation (overnight guests only, applied for after arrival)
• Address: Shibukurozawa, Tamagawa, Tazawako, Semboku City, Akita Prefecture 014-1205 (phone 0187-58-3000)

Nearby, geothermal and highland sights such as Goshogake Onsen, the Hachimantai summit and Lake Onuma are dotted about, making this an easy location to tour together with a drive. Note that Semboku City is calling for caution regarding volcanic gas accompanying the drop in the water level of Yunuma (Akita-Yakeyama).

Practical Travel Notes

To fully enjoy the rock baths and healing stays, from spring when the road reopens through the foliage season is recommended. For the popular rock-bath field, bring a mat and towel; earlier morning makes it easier to secure a spot. As the strongly acidic water is harsh, start with short soaks or a bath diluted from the source. Nearby lie geothermal and highland sights such as Goshogake Onsen, the Hachimantai summit, and Lake Onuma, easy to pair with a drive. Budget around 1,000 yen for a day bath; overnight healing stays vary with the number of nights.

A Quick Tip

Because the water is strongly acidic, start with short soaks. Use the rock baths according to your condition and keep hydrated. It stings if it gets in your eyes, so take care, and if visiting in winter, be sure to confirm whether the main Tamagawa or Shin-Tamagawa is open.

📚 Sources

The day-trip bathing hours and fees and the revision date, the hours and fees of each facility, the parking guidance, the bear countermeasures, the 2026 reopening date and traffic information for National Route 341 were confirmed on the official Tamagawa Onsen website (the hot spring, facilities and notices pages). The spring quality name, benefits, source figures and travel times follow the "Tamagawa Onsen and Shin-Tamagawa Onsen" page of the official Semboku City website. The designation date of hokutolite was confirmed in Cultural Heritage Online, "Hokutolite of Tamagawa Onsen," and its protection as a Special Natural Monument and the prohibition on collecting it in the digital collection of the Akita Prefectural Museum. Fees, hours and operating periods are subject to change, so please check official sources before setting out.

Practical Information for Your Visit

• Spring quality and indications: An acidic aluminum-iron chloride spring (hypotonic, acidic, high-temperature spring). It is said to be beneficial for neuralgia, rheumatism, skin conditions and more
• Source temperature, pH and flow rate: The source known as Obuke is 98 degrees with a pH of 1.2 and a flow rate of 9,000 liters per minute. It is the largest volume in Japan from a single source
• How the water is used: The large bathing hall has 11 different baths, including 100 percent spring water, 50 percent spring water and a weakly acidic bath. The 100 percent spring water bath is strongly stimulating, so it is kept at a lower temperature
• Day-use bathing: 10:00 to 15:00 (last reception 14:30), 1,000 yen for adults and 500 yen for children. The fees were revised on April 16, 2026. The day-use rest hall is available 10:00 to 15:00 for 1,500 yen
• Open-air bath and private baths: Tamagawa Onsen has no open-air bath. The private baths are for overnight guests only, by reservation, from 7:00 to 21:00. If you want an open-air bath, head to its sister inn, Shin-Tamagawa Onsen
• Indoor ganban-yoku (stone sauna): For overnight guests only, by reservation, with 25 beds in total, from 7:00 to 20:50. The fee is 800 yen (300 yen for members), plus 500 yen for a samue outfit and 200 yen for a bath towel. A charge was introduced on October 1, 2024
• Drinking the water: There are facilities for drinking the spring water in the large bathing hall, with guidance to dilute it 38 times before drinking
• Footbath: 8:00 to 17:00. It is available only during the period from April 16 to November 15
• Parking: Day visitors should use the "Akita Prefectural Tamagawa Enchi Parking Lot" on the left on the way down to the inn. It is open 8:30 to 16:30 and costs 300 yen per visit. Overnight guests drop their luggage in front of the inn, after which a staff member guides them to parking spaces on the loop road about 2 km away
• Access: From in front of JR Tazawako Station, take the Ugo Kotsu "Express Tamagawa Line" and get off at "Tamagawa Onsen," 70 to 80 minutes (in winter it is the "Express Shin-Tamagawa Line"). By car it is about 110 minutes from the Morioka IC on the Tohoku Expressway via National Route 46 and National Route 341. From Akita Airport it takes 180 minutes on the "Akita Airport Liner Tamagawa-go"
• Road conditions in winter: Tamagawa Onsen closes for the winter and is generally open from late April to late November. In 2026 it reopened on April 16. On National Route 341, in the spring just after the road opens and from autumn into winter just before it closes, the section between Futagamikan on the Lake Tazawa side and Sumikawa on the Kazuno side is closed to traffic at night from 19:00 to 8:00 the following morning. The inn that also opens in winter is the sister inn Shin-Tamagawa Onsen
• Preparing for bears: On the nature trail, measures have been taken including more intensive grass cutting, the installation of repellents and sound devices, and the placement of air horns inside the ganban-yoku tents, and trekking poles and bear bells are lent out free of charge. Visitors are asked to refrain from going out at night or early in the morning, to avoid bringing food or drink onto the nature trail, and to move in groups
• Barrier-free facilities: Shin-Tamagawa Onsen is presented as a barrier-free inn with handrails and floors free of steps
• How long to allow and crowding: About 1 to 1.5 hours if you only take a bath, and half a day is a safe allowance if you combine it with a walk on the nature trail or the ganban-yoku
• Other facilities: The shop is open 8:00 to 18:00; in the laundry the washing machines are free and the dryers cost 100 yen for 40 minutes. The toji (hot spring cure) consultation room is open 8:30 to 16:30 by reservation (overnight guests only, applied for after arrival)
• Location: Shibukurosawa, Tamagawa, Tazawako, Semboku City, Akita Prefecture 014-1205 (tel. 0187-58-3000)

Scattered around the area are geothermal and highland attractions such as Goshogake Onsen, the summit of Hachimantai and Lake Onuma, making it an easy place to combine with a drive. Note that Semboku City is warning about volcanic gas associated with the falling water level of Yunuma (Akita-Yakeyama).

📚 Sources

The day-use bathing hours, fees and revision date, the opening hours and fees of each facility, the parking guidance, the bear countermeasures, the 2026 reopening date and the traffic information for National Route 341 were confirmed on the official website of Tamagawa Onsen (the hot spring, facilities and news pages). The name of the spring quality, the benefits, the figures for the source and the travel times for access come from the "Tamagawa Onsen and Shin-Tamagawa Onsen" page of the official Semboku City website. The designation date of hokutolite was confirmed on Cultural Heritage Online ("Hokutolite of Tamagawa Onsen"), and its protection as a Special Natural Monument and the ban on collecting it were confirmed in the digital collection of the Akita Prefectural Museum. Fees, opening hours and operating seasons are subject to change, so please check the official information before you set out.