Tokyo used to have at least one public bath (sento) in each of its numerous neighborhoods, but their number has greatly dropped in past decades. Recently, the popularity of sento has increased a little, with the larger baths offering entertainment, dining and relaxation under one roof, and the smaller, nostalgia-imbued ones allowing bathers to be brought back to the good old days.

Tokyo is not a place where onsen water surfaces naturally, but thanks to modern boring and pumping technologies, it is now possible to get access to naturally heated water virtually anywhere if you bore deep enough. As a result, several larger bath complexes featuring hot spring water have appeared across central Tokyo.