Rusutsu Onsen - Kotobuki-no-yu

Kotobuki-no-yu (ことぶきの湯) is the onsen bath at Rusutsu Resort Hotel & Convention, on the sixth floor of the North Wing, opened in 2019. The open-air bath runs about 20 meters and looks out toward the national park mountains, though in winter snowbanks along the edge can block the view. Indoors, large glass windows light a bright bath with a cave bath (healing music plays inside), a reclining jet bath, a cold plunge, and saunas, dry on the men's side and steam on the women's. The water has a local reputation for leaving skin feeling smooth. Hotel guests bathe free with their room key card, day-use visitors pay at the front desk, and mixed bathing isn't allowed for anyone aged seven or older.