Hoshino Onsen Tombo no Yu is a hot spring facility located in the Hoshino area of ​​Karuizawa Town, Nagano Prefecture, where you can drop in and enjoy the hot spring water directly from the source. It is known as a famous hot spring in Karuizawa with a history of over 100 years since it was opened, and is popular with locals and many tourists alike. The water is soft to the touch and is also known for its skin-beautifying properties. In the open-air bath surrounded by rich nature, you can relax and enjoy the hot spring while watching the beautiful scenery of the four seasons. In particular, during the season of fresh greenery and autumn leaves, you can feel a deeper sense of unity with nature.

The water at Tombo no Yu is weakly alkaline and soft. It is said to have a skin-beautifying effect, and is popular with women.

The indoor bath is also spacious, and it is an open space where you can bathe while looking at the outside scenery through the glass. There is also a sauna, so you can relax to your heart's content. After bathing, there is a rest area and a cafe space where you can enjoy snacks and drinks made with local ingredients, so you can spend your time after bathing comfortably.

Tombo no Yu is also close to other tourist spots in the Hoshino area, such as Harunire Terrace and Karuizawa Kogen Church, so by combining your visit with these facilities, you can experience the charm of Karuizawa on a deeper level.