Saitama Seiganji Onsen
A natural-spring bath complex on a wooded Musashino plot in Saitama's Nishi ward. The source, over 600 litres a minute from 1,500 m down, is a faintly green-tinged amber sodium-chloride water; in the outdoor area the rock bath and 'source tepid bath' are filled free-flowing without heating or dilution, and the place is famous among enthusiasts for its 'nuru-yu culture' of long soaks at around 38 °C. There are also raw-source pot baths, lie-down baths, a high-concentration carbonated bath, a sauna with löyly and a deep cold plunge, and an outdoor rest area facing the trees — remarkably quiet for the suburbs. Adults ¥880 on weekdays, ¥980 on weekends and holidays; children ¥500/¥550; open 10:00–24:00 (last entry 23:30), irregular closures. Restaurant, body care and scrub treatments on site. About 25 minutes by bus from JR Ōmiya Station to 'Seiganji', or by taxi from Ageo or Sashiōgi stations. A must for tepid-bath lovers in the Tokyo area; large car park.