Yunomoto Onsen is a historic hot spring resort located in Takaharu Town, Nishimorokata District, Miyazaki Prefecture, with over 240 years of history. The spring source was discovered in 1784 (Tenmei 4), and the inn was established in 1902 (Meiji 35), making it one of Japan's oldest high-concentration carbonated hot spring resorts. It is said that senior retainers serving the Shimazu family, lords of the Satsuma Domain, used this hot spring for therapeutic purposes.

The most distinctive feature is its exceptionally rare "high-concentration carbonated spring" with a carbon dioxide concentration exceeding 1,300 ppm, which is extremely uncommon even in volcanic Japan. The spring source is a cold mineral spring at 21.6°C, which transforms from transparent to a beautiful golden color during the heating process. The bathhouse features both golden-colored heated baths and transparent cold spring baths side by side, allowing guests to alternate between them for enhanced blood circulation and parasympathetic nervous system support.

The spring quality is classified as carbon dioxide-containing magnesium/sodium/calcium-hydrogen carbonate cold mineral spring (hypotonic neutral cold mineral spring) with a pH of 6.2. The facility offers indoor baths (hot spring and cold spring) and an open-air bath, with accommodation for 30 guests in 11 rooms. Free Wi-Fi, a large banquet hall, and free parking (25 regular vehicles) are available. The inn welcomes group bookings including sports teams and school groups.