Kameyama Onsen (Kimitsu)

Kameyama Onsen Hotel

About 70 minutes from central Tokyo via the Aqua-Line, a hot-spring inn founded in 1950 on the shore of Lake Kameyama in the Boso hills. Its chocolate-brown 'kuroyu' bicarbonate water — billed as Boso's finest beauty bath — flows freely into a large bath with lake and forest views. Day use 11:30–18:00, ¥1,000 on weekdays; no day bathing Thursdays and Fridays. In autumn pair it with a foliage cruise on the lake.