HotarunoSatoBontennoYu

Relax in a famous 100% free-flowing natural spring and an open sauna overlooking Mt. Haguro

Tochigi Utsunomiya City

"Hotaru no Sato Bonten no Yu" is a natural hot spring facility located at the foot of Mt. Haguro in the northern part of Utsunomiya City, boasting remarkable freshness. The underground spring water, known as Kamikawachi Onsen, is offered as 100% free-flowing natural spring water with no added water, no heating, and no recirculation. It is colorless, transparent, and proudly smooth on the skin. The sauna is a dry sauna with powerful heat around 95°C that feels pleasant, and you can work up a good sweat in the clean, inviting interior. The cold plunge bath uses groundwater and features consistently cool temperatures throughout the year, along with a mellow texture that is gentle on the skin. Outdoor bathing while taking in the seasonal scenery of Mt. Haguro is exceptional, guiding both body and mind into a deep state of totonou as you feel the breath of nature.

Hot Spring & Bath Information

Kamikawachi Onsen

TypeNatural Hot Spring

Flow-through

A 100% free-flowing natural hot spring sourced from underground, with no added water, no heating, and no recirculation. The sodium-calcium chloride and sulfate spring water helps smooth and soften the skin, and its warmth lingers even after you leave the bath. This colorless, transparent water with no peculiar smell is an exquisite bath where you can feel the true power of a natural hot spring on your skin. Enjoy a luxurious soak in the open-air bath overlooking Mt. Haguro.

Sauna

Dry Sauna

90°C

Sauna TypeDry Sauna

Stove TypeConvection Stove (Sauna Stone)

Capacity10people

Men'sWomen's

A calm dry sauna wrapped in the warmth of wood. The steady heat radiating from the convection stove warms the room evenly and gently envelops your whole body. From sauna beginners to seasoned sauna-goers, it offers an easy and rewarding sweat session without strain. In this quiet space, you can spend your own peaceful time in a soothing environment.

Cold Bath

Cold Bath

18°C

Water QualityNatural Water (Groundwater, Spring, etc.)

Capacity3people

Men'sWomen's

A cold plunge bath filled with fresh natural water drawn up from underground. Its mellow, gentle feel on the skin is a hallmark of groundwater, instantly and comfortably cooling down a body heated by the sauna. It further enhances alternating hot-and-cold bathing with the sauna and helps switch you into a deep state of totonou. You can enjoy a blissful cooldown while surrounded by clean, refreshing water.

Business Hours

Monday
10:00〜21:00
Tuesday
10:00〜21:00
Wednesday
10:00〜21:00
Thursday
Closed Days
Friday
10:00〜21:00
Saturday
10:00〜21:00
Sunday
10:00〜21:00
Holiday
10:00〜21:00

Closed Days: Thursday

Address

〒321-0402 18-4 Imamicho, Utsunomiya City, Tochigi Prefecture

View on Google Maps

Website

https://www.bonten-no-yu.com/
Onsen & Spa Facilities (Super Sento, Sauna, Spa)

Gender Access

Gender Separated

❓
Tattoos in the Communal Bath
Unknown (Please Check)

The above applies to the communal (shared) baths. At facilities with private baths or private saunas, guests with tattoos may still be able to bathe. Please check with the facility for details.

Premium Magazine

Japan's Must-Visit Finest Onsen & Sauna Facilities

Curated by an expert who visits onsen and sauna facilities every day and has explored 300+ locations — only facilities confirmed to be truly exceptional are featured.

Learn more