The signature bath of Omaru Onsen Ryokan, this wild and scenic mixed-gender large open-air bath was created by damming up the hot spring river that flows through the grounds. It consists of three levels: Shirakaba no Yu, Ajisai no Yu, and Azami no Yu, and is fed directly by abundant water gushing from the river's source in a true free-flowing direct-from-the-source style. With bathing wear required, men and women can enjoy an exceptional hidden hot spring experience together while feeling the breath of nature all around them.

These women-only open-air baths are surrounded by abundant nature and designed so female guests can relax with complete peace of mind. There are two baths, the spacious Shakunage no Yu and Yama-yuri no Yu, which is located closer to the upper reaches of the river, and both feature luxurious free-flowing direct-from-the-source hot spring water. Guests can fully enjoy the skin-beautifying bath, rich in metasilicic acid, together with Nasu's beautiful seasonal scenery, without worrying about those around them.

These gender-separated indoor large public baths have a calm Japanese atmosphere with interiors made of cypress and stone. There is Sasa no Yu for men and Sakura no Yu for women, and each features multiple baths with different temperatures. Fresh spring water flows in 24 hours a day, the water feels exceptionally soft on the skin, and it warms the body deeply from within. A potable spring water area is also available, allowing guests to directly take in the fresh, tasteless, odorless hot spring water, which is said to be effective for gastrointestinal ailments.

A free-flowing direct-from-the-source private bath available exclusively to overnight guests for a truly private experience. In the quiet, relaxed space, you can have the skin-beautifying water rich in metasilicic acid all to yourself. Away from the bustle of day-trippers, it offers the ultimate private bathing experience, allowing families and couples to warm their bodies slowly and surrender to the serenity of a hidden hot spring at the farthest reaches of Nasu and its exceptional water quality.