If you’ve never been to Japan before, researching the rich culture and their immersive experiences – such as using an onsen, you may be asking yourself ‘what is an onsen’? Well, you might have heard of a ‘hot spring’, which is a natural stream of water that is heated by natural underground volcanic activity. These streams can vary in temperature between boiling hot and lukewarm – in fact, when these streams reach a boiling hot temperature, they often form a geyser. A geyser is a hot spring that intermittently spouts a column of very hot water and steam into the air. Hot springs and geysers are both manifestations of volcanic activity – resulting from the interaction of magma and groundwater or hot igneous rocks at shallow depths – but although geysers are a marvel that are usually wondered at from afar, hot springs (onsen) can be enjoyed up-close and many people believe that they have healing benefits.
A Japanese onsen is a natural hot spring intended to relax and heal both body and mind. As a volcanically active country, Japan is situated on a number of volcanoes and this volcanic activity naturally heats a number of water sources that pool aboveground, and from this natural occurrence, thousands of onsens have both occurred naturally and been stimulated by man-made structures.
In some cases, the term onsen actually broadens to cover the ryokans (traditional Japanese guest houses) and bathing facilities around the natural hot springs. The volcanic nature of Japan provides plenty of natural water hot springs with distinctive minerals or chemicals. Some examples of these onsen include sulphur onsen, sodium chloride onsen, hydrogen-carbonate onsen and iron onsens. There are around 3000 onsen across Japan. Some outdoor onsen can be enjoyed while it is snowing, which is an interesting experience and one I recommend!
Onsens can be found in many shapes and sizes, from small tubs to huge outdoor pools; onsen can be run both run by the local government and owned privately (often as part of a hotel or ryokan). The indoor baths are usually called uchiyu and the outside baths are usually called roten-buru. Baths were traditionally located outdoors, but a great number of private establishments have now created indoor onsen. These indoor onsen are not the same as sentō, which are indoor bath houses where public baths are available to customers to be filled with heated tap water.
Most traditional communal onsen are separated by gender, although children of both sexes can be found with their parent in either sex’s bath. Most private onsen will have the option to hire a “private” onsen bath, where all genders and families can bathe together. These private onsen are also used by patrons with tattoos, since tattoos are prohibited in most onsens due to their taboo in Japan.
Proper etiquette is expected to be upheld while using onsen. Before use, all guests are expected to thoroughly wash themselves before use. Bathing stations are equipped usually with stools, wooden buckets, faucets and all useful toiletries. The use of onsen while still dirty or soapy is unacceptable and you may be asked to leave. Additionally, most guests are expected to bring a small towel to use as a wash cloth. For guests who may get dizzy, this wash cloth can be rinsed with cold water and placed on the forehead to alleviate syptoms. The same wash towel can also provide modesty when walking between the showering area and the onsen itself. There are some onsen (usually mixed) where users are allowed to wear swimsuits or a towel into the bath, but most have signs prohibiting this and this would be considered unclean. Towels are usually left on the side of the water while using the baths. When using private onsen, towels are usually provided for patrons. Most onsen are quiet and relaxing, but a growing number of them play ‘natural’ music such as piped instruments and the sounds of flowing water. Most bathers will engage in quiet conversation during relaxation, but rowdiness is prohibited. Small amounts of excess energy and splashing around is usually tolerated by children.
Tattoos were originally banned to keep out Yukaza (crime gangs) from onsen. These Yukaza traditionally have elaborate full-body decoration. Around 56% of onsen operators have currently bathed bathers with tattoos from using their facilities, and some others will only allow them only to use private onsen. However, tattoo-friendly onsen do exist. In 2015, the Japan National Tourism Organisation found that around 30% of onsen operators at private establishments would not turn away a customer with tattoos, and an additional 13% said that they would grant access to tattooed patrons should they cover up their tattoo. There are a growing number of onsen that are happy to allow tattooed patrons and mixed gender bathing, but you should ensure you investigate this before going to one if you have tattoos.
Make sure that you’re aware of the risks before you go. Millions of Japanese people and tourists bathe in onsens every year with few side effects, there are potentially some risky effects such as aggravating high blood pressure and heart disease. Bacteria have been found in some onsens with poor sanitation, however the local authorities and hot-spring communities have improved regulation to maintain their good reputation. Fewer than five cases of infectious disease have been seen historically in hot bodies of water in Japan, which is low in comparison to the worldwide statistics. Most onsen request that anyone with open cuts and sores should not bathe, and some onsens add chlorine to their waters to prevent infection although most prefer the natural, unchlorinated onsens that do not recycle their water use but instead clean baths daily.