Two halves: the swimsuit spa zone 'Yunessun' and the traditional nude 'Mori no Yu'. Wine baths, coffee baths and water slides make it family-friendly and an easy first onsen for visitors. Tattoos allowed if covered with a sticker. Dynamic pricing in 2026: passport (both zones) from ¥3,500, swimsuit zone from ¥2,500, Mori no Yu only from ¥1,500.
A giant bath complex next to Tsutenkaku Tower in Shinsekai. The 'Europe zone' (Rome, Greece, Mediterranean) and 'Asia zone' (Bali, Persia) swap between men and women each month. There's also a swimsuit pool, stone saunas and hotel floors. Open 24 hours, so it doubles as a place to stay after the last train. Tattoos OK if covered with a sticker.
Arima's biggest day-spa complex: gold spring, silver spring and (artificial) carbonated baths — 26 baths plus stone saunas, with loungewear and towels included. Free shuttle from Arima-Onsen Station.
Founded in 1691 and regarded as Japan's oldest surviving hot-spring inn building, this Shima Onsen institution in Gunma stands across a red bridge; the main house, said to be one of the models for the bathhouse in Spirited Away, is an Important Cultural Property. The celebrated Genroku-no-yu, built in 1930 in Taishō-romantic style, has five tubs set into a stone floor lit by arched windows, with water welling up from below. Shima's sulphate water is counted among Japan's three great baths for digestive ailments and can be drunk. Day use 10:00–17:30 (last entry 17:00), ¥1,500 with face towel, covering Genroku-no-yu, the mixed rock bath and private baths. Tattoos accepted if covered with stickers. About 40 minutes by bus from Nakanojō Station to the Shima Onsen terminus.