Bathing culture in Japan began in the 6th century, and public bathhouses became vogue in the 17th century during the Edo period. Having a bathtub at home only became commonplace after World War II, and before that, public baths in each neighbourhood were where residents went to get clean and socialize with their neighbours.
Two terms that are frequently used when it comes to public baths are onsen and sento. The former simply means hot spring, while the latter refers to public baths in general.
Now, the most common image of sento are small, simple neighbourhood bathhouses with one or two baths usually filled with hot tap water and added minerals. Some neighbourhoods in Tokyo still retain a handful of sento. More recently however, large bath complexes known as super sento have emerged offering a variety of services and multiple baths.
Onsen or hot springs, on the other hand, are typically located in volcanic regions. The most famous onsen towns in Japan are Kusatsu Onsen, Arima Onsen and Gero Onsen. Within the towns, there are public bathhouses, which are often called sotoyu, and baths inside a ryokan accommodation, which are typically called nakayu.
Below is a collection of public baths in Japan, from Hokkaido to Kyushu.