Jinseki Kōgen Onsen
A day-use hot spring in Jinsekikōgen, a plateau town at 500–700 m in eastern Hiroshima. The source, discovered in 1994 in the Iseki district of former Sanwa, is a rare pH 10.2 strongly alkaline, weakly radioactive cold mineral spring – low in irritants and gentle on the skin. The slightly cloudy, viscous water lifts excess oil and leaves skin smooth, which locals call a 'natural beauty serum'. Inside are an indoor bath, open-air bath, sauna and cold plunge, plus a rock-bed spa, carbonated tub and a private family bath, with a rest area and restaurant. Adults pay ¥900 and children of elementary age or under ¥500; coupon books and a monthly pass keep the regulars coming. Open 10:00–21:00, closed Tuesdays, parking for 20 cars. About an hour by car from central Fukuyama via Route 182, or 2 minutes on foot from the Iseki-naka bus stop. Pair it with Taishaku Gorge, Jinseki beef and stargazing on a drive across the highlands.