Sunriver Oboke is a hot spring hotel located in the scenic Oboke Gorge within the Tsurugi Quasi-National Park, in Yamashiro-cho, Miyoshi City, Tokushima Prefecture. Its greatest appeal lies in the spectacular views of the gorge carved by the Yoshino River over 200 million years through the Shikoku Mountains. The hotel opened as a public lodge in 1979. The main bathhouse and outdoor bath offer panoramic views of the fantastical rock formations of Oboke-Koboke and the azure waters of the Yoshino River across all four seasons. The surrounding area is also famous for its yokai (supernatural creature) legends, with over 150 tales including the legend of Konaki-Jijii (the Crying Old Man).

The spring water is classified as an alkaline simple hot spring with a strongly alkaline pH of 9.57. The source temperature is approximately 20 degrees Celsius as a cold mineral spring, heated for bathing. The water is colorless and transparent with a distinctively slippery texture, earning it the nickname of a spring that makes cosmetic lotion unnecessary — a beautifying bath highly regarded among locals. The water contains fluorine ions that promote metabolism. Therapeutic indications include neuralgia, muscle pain, joint pain, cold sensitivity, skin conditions, and skin beautification.

The facility offers indoor baths (one each for men and women), outdoor baths (one each for men and women), and a sauna. From the nature-facing bathhouse, bathers can enjoy views of the Koboke Gorge and the Yoshino River, renowned as one of Japan''s most powerful rapids, while experiencing the seasonal transitions from spring verdure to autumn foliage to winter snowscapes. The on-site restaurant Satoyama serves cuisine prepared with local ingredients. Accommodation is available in 25 rooms (8 Western-style, 15 Japanese-style, 2 combined). Day-trip bathing costs 700 yen for adults and 350 yen for children, available from 12:00 to 21:00.