Yunohana Otaru Onsen

This is a big day-use spa on the edge of Otaru, built for a full afternoon rather than a quick soak. The bathing area splits into a Japanese-style and a Western-style hall that swap between the men's and women's sides daily, so a repeat visit doesn't feel like the last one. Between them the halls offer several baths, an open-air tub, jet baths, waterfall-style utaseyu, and a cold plunge, plus a regular sauna and a separate mist sauna that runs a steady haze from the ceiling. There is also a ganbanyoku hot-stone room. The water is drawn from a natural hot spring. Upstairs, a restaurant and a wide rest area give the place a proper half-day rhythm, and towels and toiletries are provided, so it works fine hands-free.