Miya no Yu is a thermal spring located in eastern Tokyo near the Chiba border. It offers an indoor bath, an outdoor rotenburo and a sauna, making it an easy day trip from the capital.
Insider tip — Miya no Yu ('Palace Bath') in the greater Tokyo/Chiba area — likely a neighborhood sento (public bath) or a drilled 'urban onsen' facility. In the greater Tokyo metropolitan area, many baths claim 'onsen' status by tapping deep geothermal wells. Verify if this is a certified natural onsen or a heated sento before visiting.