Surrender yourself to the ancient hot water
Cultivate energy for tomorrow

Since its opening in 1915, Hoshino Onsen has been loved as a famous hot spring in the summer resort of Karuizawa. It is said that many cultural figures, such as Hakushu Kitahara and Akiko Yosano, also immersed themselves in the water. Hoshino Onsen Tombo-no-yu is a drop-in hot spring that draws on the history of Hoshino Onsen. While feeling the forest with your whole body, you can relax your mind and body in the ancient hot springs and fully nourish your energy.

Characteristics of hot springs

Flowing over the source

All baths at Tombo-no-yu are fed by natural hot spring water.
The bathtub is filled with high-quality hot spring water from Hoshino Onsen, and the soft water is said to be ``hot water for beautiful skin.''
As proof of the freshness of the hot springs, we also have taps for drinking the hot springs. The bath water is neither recirculated nor supplemented; it is completely replaced daily.

A relaxing space that blends into nature

An indoor bath, an open-air bath, and a pond are all connected, and the changing time and seasons are reflected on the water surface.
The interior is made with natural materials, with plenty of cypress and natural stone. The indoor bathtub is deep enough to comfortably soak up to your shoulders (men's bath 90cm, women's bath 85cm).
Enjoy the comfort of being surrounded by nature in a space that is integrated with the surrounding trees.


The temperature is about 80-90 degrees. It uses an auto-rolling system that runs once every 20 minutes.
You can enjoy the seasonal scenery from the window while listening to the background music of jazz.
The water bath uses spring water from Wild Bird Forest, and maintains a stable water temperature of approximately 13 degrees all year round.
Once you've worked up a sweat, we recommend taking a bath outside in Karuizawa's clear air.

Seasonal changes

You can fully enjoy the changing seasons: cherry blossoms and buds in spring, deep greenery in summer, red leaves in autumn, and snow in winter. We also hold seasonal baths such as apple bath in autumn and yuzu bath during winter solstice.
The piece of art ``Shinra Hyakusen''(``a hundred selections from all of nature'') is set at the entrance of each men's and women's bath. The calligraphy and paintings convey the richness of nature surrounding Hoshino Onsen Tombo-no-yu, and change depending on the season.

Introduction to hot springs

Hot Spring Type

Simple hot spring (hypotonic slightly alkaline high temperature spring)

Amount of discharge

400 liters per minute

Recommended uses

Chronic lower back pain, sensitivity to cold, recovery from fatigue, etc.

Enjoyment after taking a bath

Café Hungry Spot

The adjacent Café Hungry Spot offers seasonal drinks, craft beer, soft serve ice cream, and more. It is recommended as a resting place or a meeting place.

See more

Natural bathing place

After taking a bath, why not sit on a bench in the shade of a tree and take a breather while feeling the highland breeze?

Business Information

Opening hours
10:00-22:00 (last entry 21:15)
*Limited hours on July 5th and 6th, open from 17:00 to 22:00 (last entry at 21:15)


Usage fee

Adult 1,350 yen / Child (3 years old to elementary school student) 800 yen
*During Golden Week (April 27th to May 6th), summer, and New Year's holidays (December 29th to January 3rd), special rates apply: Adults 1,550 yen / Children 1,050 yen

Facilities in the bathhouse

Indoor bath, open-air bath, sauna, cold bath, drinking spring


Body soap, shampoo, conditioner, lotion, emulsion, cleansing wash (women's bath), hair dryer, towels (rental towel set 350 yen, bath towel sales 200 yen), baby bath

User Guide

・Bathing for infants and toddlers: As the temperature of the indoor bath is high and the bathtub is deep, we recommend using the baby bath or open-air bath.
・Bathing with children of the opposite sex: Children under the age of 6 may bathe together.
・As a general rule, people with tattoos are not allowed to enter, but they may enter the bath if they can cover them with eight stickers (each 8cm x 1cm).

Estimated usage

Prohibited matter

  • Use of electronic devices
    Please refrain from using electronic devices such as mobile phones in the bathing area and beyond the changing area. It can be used at the entrance of the building.

  • Bathing while intoxicated

  • Bathing with tattoos visible

How to enter a hot spring

  • Please wash your body before entering.

  • Please tie long hair and avoid letting it get in the bathtub.

  • After using the sauna, please thoroughly rinse off the sweat before entering the cold bath or bathtub.

  • Please do not soak the towel in the bathtub.

  • Please refrain from taking up space in the shower or sauna.

Hoshino Onsen Tombo-no-yuFAQ

Can I use it even if I am not staying at a hotel in the Hoshino area?

Tombo-no-yu is a day trip hot spring facility. You can use it regardless of whether you are staying overnight or not.

Can I re-enter?

Re-entry is possible within 4 hours on the same day. Details will be provided at the Tombo-no-yu reception counter.

Can I use it in bathing clothes?

Only bathing suits designed to cover scars from surgeries or other wounds are allowed for. However, we do not provide them for rental.