Iwaki Yumoto Onsen Iwaso

A former kappō inn in Iwaki-Yumoto reborn as a bargain onsen stay: a top-floor, free-flowing sulphur bath open all night and the okami's homemade-jam breakfast — but there's no dinner, no private bath, and it's an old building with dark corridors at night

Iwaso is a six-storey, 19-room inn on a quiet street of Iwaki-Yumoto, a spa town that bills itself as one of Japan's three oldest hot springs. It was once a kappō ryokan known for its food; magazines in its small library show dinner was still served around 2017, and the unused dinnerware is now sold off in a lobby corner. Today it offers only room-only or breakfast stays, from about ¥5,500–7,700 per person. The draw is the glass-walled bath on the top floor, which looks over the town to the hills where the sun rises. The water is Yumoto's sulphur–sodium chloride spring (pH 8.0, 58.3°C), free-flowing and open from 15:00 until 9:00 the next morning. The second draw is breakfast in the lobby lounge: eggs fried or scrambled to order, small home-style dishes, and toast with the okami's homemade jams. Japanese guests rate it 4.7 across 495 reviews on one major site (breakfast 4.8, bath 4.6) and 4.22 across 407 on another. Bloggers who stayed from 2022 to 2025 praise the spotless if dated building, fresh flowers, generous bath amenities, a goodbye at the door and the six-minute walk to the station. The 2026 complaints are about age: lobby and corridor lights switched off by about 22:00, a boiler failure in March that sent guests to bathe at another hotel, a stiff door lock, a stink bug in the bath, and big windows that may be visible from outside. Rooms vary widely, from 4-tatami singles to roadside 'discounted' rooms in the old wing.