As with many words in Japanese, the word “onsen” (温泉) has different meanings. The two main meanings are either a hot spring, or a group of traditional inns and hotels that have been developed around a hot spring. For the purpose of this blog, we will use the latter meaning.
Since it is a geothermally-active country, Japan has thousands of onsen scattered throughout the country. There are many different types and sizes. They range from remote single-bath facilities to mega-reosrt complexes with many multi-story hotels surrounded by numerous souvienir shops and pachinko parlors. Today, most traditional inns and hotels are self-contained with everything guests will need during their stay, so guests don’t need to leave the facility. But many onsen also have public baths at different locations around the onsen that can be used by anyone. These public baths will always have a small entry fee, and will sometimes offer free entry for people staying locally. At onsen with popular public baths, you will often see people walking around in their yukata (cotton kimono).
An onsen (温泉), is often indicated by the symbol ♨ or the kanji 湯 (yu, meaning “hot water”). Sometimes the simpler hiragana character ゆ(yu), understandable to younger children is used. Individual baths also come in many types. Initially, baths were outdoors (露天風呂 rotenburo). But today, most hotels will include both indoor and outdoor baths, often with multiple baths, each having different mineral water and/or water temperature. Different minerals provide different health benefits, and all hot springs have a relaxing effect on both body and mind. The majority of baths today are gender-separated, but in some of the more remote onsen mixed gender baths can still be found. All baths are used with no clothing.