Kawayu Onsen Sansuikan Kawayu Midoriya

Kawayu Onsen Sansuikan Kawayu Midoriya is a riverside ryokan in Hongu, Tanabe City, Wakayama Prefecture, on the Otogawa River not far from Kumano Hongu Taisha. Kawayu Onsen is known for hot water that wells up from the riverbed, and in winter a huge open-air bath called Sennin-buro is dug into the gravel bank. The inn stands about a two-minute walk from the Kawayu Onsen bus stop and has more than 80 guest rooms.

The water is a sodium-bicarbonate-chloride spring, and both the large indoor bath and the riverside open-air bath use fresh source water with no recirculation. It is traditionally said to ease neuralgia, muscle and joint pain, and sensitivity to cold.

The baths are a large communal bath overlooking the river and an open-air bath on the riverbank. The riverside bath is mixed-gender and bathers wear a bathing gown. The baths are open from 5:00 to 24:00, closed for cleaning from 10:00 to 14:00. In winter the Sennin-buro is also available within walking distance.