Yunomoto Onsen (湯之元温泉): Carbonated Springs at the Foot of Kirishima
A storied inn beloved by locals—and quietly frequented by notable figures—offering multiple carbonated baths with rare, high concentrations.
Yunomoto Onsen (湯之元温泉) sits at the foot of the Kirishima mountain range in Miyazaki Prefecture. Beloved by locals—and quietly frequented by notable figures—it’s a storied inn known to those in the know.
It’s about a one-hour drive from central Miyazaki City. Said to have been discovered in Tenmei 4 (1784), the spring lies tucked away in greenery with views toward the Kirishima peaks. There are three baths: an unheated, high-concentration carbonated spring（高濃度炭酸泉）flowing straight from the source; a lightly warmed open-air bath with a medium concentration of carbonation; and a reddish-brown mineral bath.
The standout is the cold, high-concentration carbonated spring at 22 °C—your whole body is instantly cloaked in fine bubbles, with a gentle, pleasant tingling unlike anything ordinary cold springs provide.
It’s a feeling you’d never get from an ordinary cold spring. When measured, the free-flowing high-concentration bath came in at 1,800 mg/L—far above the 1,300 mg/L listed on the analysis sheet and the highest I’ve ever experienced.
Even the slightly warmed open-air bath exceeds 1,300 mg/L, and the reddish mineral bath measures around 300 mg/L. Being able to sample carbonated springs with such different temperatures and concentrations all in one place feels like pure luxury.
I ended the day with sunset sinking behind the Kirishima range, a dinner of local specialties, and a quiet, restorative night in Miyazaki.
