(GMT)04 FEB 2017 GLA2CU:
See the sento below, why don't you try the sento?
Yes it's fully naked!
The sento (public baths) are similar to the onsen except for the water that is heated artificially.
The water of the sento is usually tap water without many mineral properties.
Sento are easily found in urban areas. Public baths are a unique part of Japan's popular tradition.
In ancient times the Japanese houses had no bathroom, and so every neighborhood had a sento.
The sento in practice were considered a primary zone of the neighborhood where to meet. Nowadays all the houses have their own bathroom, but despite this the number of sento continue to grow and develop.
Trip to sento is one of the most interesting activities to those who want to experience a Japanese culture. Don't forget you should be fully naked.