Onsen are natural hot spring baths.
If you want to visit an onsen, you should know some rules of etiquette for onsen.
First, you must remember to clean yourself before you get into the bathtub.
Then you can take a small towel into the bathroom with you, but you mustn’t let it go into the bathtub.
After enjoying bathing, you can dry yourself with a large towel in the changing room.