An observatory large public bath with panoramic views of the Utsukushigahara Plateau mountains through its large windows. The gentle water, heated from Utsukushigahara’s pure spring water, soothes the fatigue of sightseeing and travel. Guests can enjoy a luxurious bathing experience while watching the sky change colors over time, and, when weather conditions are right, gazing out over a sea of clouds. The men's bath is called Unkai no Yu, and the women's bath is called Sanraku no Yu.

A private semi-open-air bath available only during the green season from April to November. Open the windows and step out onto the terrace, and the clear highland breeze of Utsukushigahara Plateau will sweep over your warmed body, offering a blissful outdoor air-bathing experience. In a private space free from interruptions, you can fully enjoy a sense of unity with nature. There are two types: Yuuhi no Yu and Akatsuki no Yu.