Japan is an incredible country with many different and interesting facets. One of the most popular things to do in Japan, especially for foreigners, is to visit one of its onsen. Onsens are natural hot springs that people can go to and bathe in as a way to relax or cleanse themselves. 

Onsens can be found in many places, but one of the most popular spots for foreigners to visit is at an inn called Ryokan. At these types of hotels you will often find indoor and outdoor pools where you can swim in between taking baths in their hot springs or even have a sauna! 

What is an onsen? 

An onsen is a hot spring that is fed by natural geothermally heated underground water reservoirs. It’s praised for its health benefits for both the body and mind. As a volcanically active country, Japan has well over 25,000 natural springs scattered throughout the country. If you were to visit a different one each week it would take more than a lifetime to visit them all! 

The difference between Onsen and Sento

A sento is also a public hot bath but the water does not come from a natural spring, this is regular piped water just as the water you get from your sink at home. You can also come across Super Sento in Japan, these are a kind all-in-one attraction generally including different kinds of baths, saunas, and restaurants.

How to Onsen: The 101 Onsen guide in Japan and Etiquette

In modern day Japan, onsen continues to play an important role in the culture and it’s a beloved and luxurious outing for many Japanese to visit an onsen. Travelers that are brave enough to dip their feet in should be aware of the social etiquette that must be followed when visiting these natural hot springs. It’s important to follow these strict rules or your visit may be cut short or see you banned altogether! Although it can be daunting to newcomers to initially overcome the naked aspect of onsen, it’s a unique way to experience a part of Japanese culture and it should not be missed! 

1) Leave all your belongings in the locker room. 

You can only take a small towel with you into the onsen area. Often there will be a locker room available to put all personal belongings in. Small towels can be rented out at the front desk or you can bring your own in. What puts off many travelers and even some expats, is the naked aspect of it. 

2) Thoroughly wash your entire body before entering the hot springs. 

There will be individual faucets with small stools where one can sit and scrub themselves down. Body soap and shampoo are also provided but you can bring your own if you wish. After completely rinsing yourself off, make sure to rinse down your washing area, including the stool you sat on! 

3) Enjoy the mineral-rich waters and take in the beautiful natural views! 

You can take a small towel to cover yourself up while moving between the various types of baths available in the onsen. Often each bath will have different water temperatures and minerals, including a steam room. 

4) Tattoos are prohibited! 

In Japanese society, tattoos are often associated with the yakuza (organized crime syndicates in Japan), so any travelers with tattoos may be turned away at onsen establishments. However, due to the much anticipated Olympic Games in 2020, an increasing number of ryokan and onsen have been more open to accepting individuals with tattoos. To avoid offending or making any Japanese feel uneasy, cover tattoos with a small towel. For those who have tattoos that can’t be easily covered up, you can privately rent an onsen (貸し温泉). 

5) No hair and no towel inside the water

Long hair must be tied up. Hair should not come into contact with the waters, as the oils in the hair affect the quality of the spring waters. 

Also wash towels should not come into contact with the bath water for sanity reasons. When relaxing in the spring waters, the Japanese will often rest the towel on their head. 

Private Onsen and Ryokan

For those who really can’t bear the thought of stripping off in public, there’s the option to privately rent an onsen. Many ryokan will have guest rooms with private rotenburo baths attached and in some inns there will be public baths that are available for private use on request. Couples that are traveling together can also make use of this service. 

Mixed-Gender Hot Springs

Throughout the history of onsen, mixed gender bathing was the norm, which horrified Christian missionaries in the 1500s. During this time many Europeans believed that daily bathing was harmful to one’s health and the missionaries tried and failed to scale back the practise. The Japanese saw their foreign counterparts as lowly and unhygienic beings which may have been the cause for their resistance to religious conversion. After hundreds of years of tradition, the custom of mixed bathing was broken in the 1950s, when female members of the Japanese parliament voted for a new law to segregate the male and female baths. 

Though Japanese hot springs are now gender segregated (with the exception of a few places), to be fully exposed while bathing with family, friends and strangers can be difficult for some to overcome in the beginning. However, the many health benefits of onsen and the insight into Japanese culture are well worth the plunge! 

The History of Onsen 

Onsen has been an integral part of Japanese culture and society for a millennia and since its inception it has been considered to be a gift of the gods. Initially these natural hot water springs were discovered by ancient hunters who stumbled across them when pursuing wounded animals. Animals would instinctively seek these remote bubbling pools to soothe their pain, unknowingly teaching the hunters of the healing properties of the springs. 

To this day, there are many onsen facilities with statues of brown bears and white herons commemorating them as messengers of the gods, sent to lead man to these divine waters. However, it wasn’t until the arrival of Buddhist monks in 552 AD, that onsen rose in prominence and popularity. Bathing was closely tied to Buddhist purification rituals. As part of their practice to attain enlightenment, monks would immerse themselves into the divine waters to cleanse their bodies, washing away the sins of the mortal world. Stories of how the waters could cure diseases spread across the land and soon the sick began joining the monks in the religious baths, seeking the healing properties of the mineral-rich waters. 

Although onsen is known for its health benefits and as retreats for relaxation, these springs have also played a major social role not only in history but in modern society as well. Hadaka no Tsukiai (裸の付き合い), meaning ‘naked relationship’ is a phenomenon which only occurs in an onsen setting. It describes how new relationships can be formed when certain social barriers held up by uniform or hairstyle (this heavily applied in the Edo period when warriors and merchants would wear distinctive hairstyles to showcase their social class) fall away, allowing bathers to relax and communicate with each other on an equal footing. 

The Health Benefits of Onsen 

Before conventional medicine, it was believed that a visit to the local hot springs could cure any injury or ailment. While this isn’t necessarily true, onsen waters do have a number of healing properties. However, not all springs are the same. Depending on the location of the onsen, there can be many different variations of mineral composition in each natural hot spring that have different therapeutic effects. 

Knowing more about the types of minerals that are formed naturally in the hot waters can help you better enjoy the onsen experience. 

Below is a list of the different types of Japanese spring waters including their health and beauty benefits: 

Sodium Bicarbonate Saline Hot Springs 炭酸水素塩泉 

Locally known as Bihada no Yu meaning beautiful skin waters, these clear alkaline springs gently remove dirt and excess oils to give bathers soft, smooth and radiant complexions. 

Sulphur Hot Springs 硫黄泉 

You’ll know when you’ve come to access a sulphur spring due to the milky white appearance of the water and the smell of rotten eggs. Don’t let the smell put you off though. Due to its high content of hydrogen sulphide, it’s said to have therapeutic effects for people suffering from chronic bronchitis, diabetes and high blood pressure. Sulphur is also known as a natural cure for acne and blemishes. 

Perhaps this is the reason why the Japanese are known for their naturally clear complexions. 

Acidic Hot Springs 酸性泉 

Owing to the sulphur, aluminum sulphate and chloride in the water, these acidic springs have natural antibacterial qualities that can ease stiffness, muscular pain and various symptoms associated with gynaecological problems and chronic fatigue.

The effects and stimulation of these spring waters can be very strong, so this onsen is not recommended to older or sick people. Those with sensitive skin will find the acid to be irritating. After taking this acidic onsen, make sure to wash off all the onsen water with fresh water. 

Sulfate Hot Springs 硫酸塩泉 

There are 3 types of sulfate springs: sodium, magnesium and calcium. Soaking in the waters of these springs are said to help chronic constipation and arteriosclerosis as well as speed up the healing process of cuts and bruises. 

Iron Hot Springs 鉄泉 

There are 2 types of iron springs: carbonated iron and melanterite springs. These distinct red-brown waters are known for increasing the body’s own iron levels and relieving aches and pains associated with poor circulation and arthritis. 

Chloride Hot Springs 塩化物泉 

The high content found in chloride springs is said to heal cuts and burns. These springs help retain body hot and will leave bathers feeling warm long after exiting the waters. A popular choice during the cold winter months! 

Carbonated Water Hot Springs 炭酸泉 

These springs are notable for the unique sensation given off by the tiny bubbles sticking to bathers skin. The carbonated bubbles are said to help blood circulation and improve the overall appearance of skin. Lately in Japan and Korea, it’s been a popular trend amongst young women to cleanse their skin with carbonated water for similar effects. 

Radioactive Hot Springs 放射能泉 

Last but not least is radioactive springs. These waters contain a concentration of radon. Radon is a weak radioactive substance produced by the decay of radium. The Japanese believe in the Radiation Hormesis Effect, that low doses of radon exposure can improve the metabolism and boost the body’s immunity system. This is a rather controversial topic as there are still many countries that are in nonacceptance of this effect and believe that radiation leads to poor health. 

Best onsen in Japan 

From the big bustling cities to the great outdoors, you will never be too far from a hot spring facility. 

Be on the lookout for these marks! ♨ and 湯 are used to denote an onsen location on maps. 

Dogo Onsen 

Dogo Onsen is one of Japan’s most famous and oldest hot springs. With a history spanning back 3,000 years, it is believed to be the original onsen. It has been visited by many prestigious guests including the Imperial family. Studio Ghibli fans will instantly recognize the ancient bathhouse as it was the inspiration behind the Aburaya bathhouse in Spirited Away. It’s located in Matsuyama, Ehime Prefecture. 

Akita Prefecture 

Although onsen can be found throughout all of Japan, some of the best onsen can found in the northern region of Honshu, the main island. Akita Prefecture is famous amongst the Japanese for the beautiful woman with snow white skin. This may be due to the long harsh winters and number of onsen towns scattered throughout the region. Some of the most famous ones include Nyuto Onsen , Aki no Miya Onsen and Oga Onsen . 

Unzen Onsen 

Arguably the most famous onsen in Kyushu amongst tourists is Beppu Onsen but Unzen Onsen is the local favorite. Located in Nagasaki, it’s known for the clouds of vapor and smoke engulfing the mountainous scenery surrounding the pools thus earning its nickname the Hell of Unzen. 

Sakunami Onsen 

Located outside of Sendai city in Miyagi Prefecture is the mountain-top hot spring retreat, Sakunami Onsen. It has stood for over a millennia and has seen a great deal of history from feudal wars, natural disasters and rapid industrialization. However, it has always remained a vital part of the community as a center of health and restoration. It’s one of the few places that has continued the tradition of co-ed bathing. 

Jinata Onsen 

One of the most unique onsen can be found a few hours away from Tokyo on the volcanic island of Shikine-Jima. The iron-rich hot springs of Jinata Onsen are humble rock pools just meters away from the sea, offering bathers stunning views of the rolling waves.