Hidden deep in the mountains of Otari, Nagano, Amakazari Kogen Onsen is a secret hot spring that feels worlds away from everyday life. Located about 100 meters below Mount Amakazari, this natural open-air bath is surrounded by untouched beech forests and flowing mountain streams. It’s one of the most tranquil outdoor onsens in the Hakuba Valley—perfect for travelers seeking a quiet escape in nature.

This rock-lined hot spring sits in a peaceful forest clearing, with mineral-rich water flowing directly from its natural source. In summer, sunlight filters softly through the trees as you soak, while in autumn, brilliant red and gold leaves surround the bath. The atmosphere shifts with the seasons, offering a truly immersive mountain onsen experience that captures the beauty of Nagano’s changing landscapes.

Amakazari Onsen is simple yet beautifully maintained. A short flight of steps leads from the road to two open-air baths separated for men and women. Parking is available nearby for up to seven cars, making it an easy stop for those exploring the Hakuba Valley.

The hot spring water flows directly from the source, known for its soothing minerals that ease fatigue and muscle tension. After a long hike or day of sightseeing, soaking here under the open sky is a deeply relaxing way to experience Japan’s natural beauty.

There are no showers or modern amenities. The changing rooms and toilets are kept clean, and visitors are encouraged to leave a small donation in the offering box as a token of gratitude for this free public onsen.

Unmanned, peaceful, and surrounded by untouched nature, Amakazari Kogen Onsen remains one of Nagano’s best-kept secrets. With no crowds, it offers a rare moment of stillness and connection with the mountains. Whether you visit in the lush green season or during the golden autumn months, this hidden onsen is a hidden representative gem of Japan’s quiet beauty.

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Where is Amakazari Kogen Onsen located?

Amakazari Kogen Onsen is located in Otari, Nagano Prefecture, about 100 meters below Mount Amakazari. It’s easily accessible by car and about a 40-minute drive from Hakuba Village. The onsen sits in a quiet beech forest surrounded by mountain scenery.

Is Amakazari Kogen Onsen free to use?

Yes, the open-air baths are free for public use. Visitors are encouraged to leave a small donation in the offering box inside the changing room to help maintain this beautiful natural hot spring.

Are the baths separated by gender?

Yes, the onsen is divided into men’s and women’s sections halfway up the short staircase. Each area has its own open-air rock bath and small changing room.

Are there showers or indoor facilities?

No, this is a completely natural outdoor onsen with no showers or indoor baths. There are clean changing rooms and toilets nearby, but please bring your own towel and toiletries.

Is there parking nearby?

Yes, there is a small parking area near the entrance that can accommodate around six to seven cars. From there, it’s only a short walk up the steps to the hot spring.

What should I bring?

Bring a towel, water, and a small bag for your belongings. As this is a natural setting without staff, it’s best to prepare in advance and take any trash home with you.

When is the best time to visit?

Amakazari Kogen Onsen can be visited year-round except in the winter months when the road is blocked, but it’s especially beautiful in summer when sunlight filters through the trees and in autumn when the forest glows with red and gold leaves.