Types of Japanese Onsen You Need to Know About

Amidst snow sustaining temperatures,
people and beasts alike,
rest in steaming waters.

Japanese macaque monkeys enjoying the onsen in Nagano

If you ever travel to Japan, there are certain things you must do: eat the freshest sushi you can find, drink locally made sake, climb Mt. Fuji, take a ride in the bullet train, etc. But many people tend to miss out on the most traditional and amazing Japanese experience there is: relaxing at an onsen.

What's an onsen?

The Onsen (温泉) refer to the Japanese spa facilities built around natural hot springs. Since Japan is a volcanic island, there are more naturally occurring hot springs than anywhere else in the world. 

There are over 30,000 naturally occurring hot springs and 3,000 onsen resorts in Japan. For comparison, the US only has around 1,600 naturally occurring hot springs and less than 100 hot spring resort.

FREE GUIDE - 7 HIDDEN SNACK STORES OF TOKYO

What makes an onsen experience so special is that it's rooting in thousands of years of tradition and is considered one of the best ways to relax and take your mind off of things.

Different Types of Onsen

While there are many types of onsens, there are certain criterias in order for a hot spring to be considered an onsen.

• Osens are defined as hot water that springs from the Earth, either naturally or from artificially bored holes.
• The onsen water needs to be higher than 25°C or 77°F
• It needs to have at least 1 of 19 different types of minerals

There are a total of 19 different types of baths, which are classified by their mineral composition. These minerals have long been regarded by the Japanese to aid in illness and injury. The theory is that the minerals contained in the onsen water are absorbed through your skin into your body, to provide various medical benefits.

Sulphur Onsen: The first Sulphur onsen are known for their distinct smell and milky color. Believed that they can help treat skin disorders and arthritis. The most popular,Tamago-yu, Takayu Onsen, Fukushima.

The waters here flow 100% direct from the hot spring source, which is the most sought after type of onsen.

Iron Onsen: These onsens are rich in iron and the water have the color of rust. It can be found inIkaho Onsen. This type of spring helps the body's ability to retain heat, and when consumed replenishes the body's iron levels, beneficial for anemics.

Alkaline Onsen: Alkaline soda hot springs likeOsaka’s Saksuikan Onsen, are suggested for women as they supposedly add femininity to the bather.

Hydrogen Onsen: Hydrogen carbonate hot springs, rich in carbonation are a blast as the fine bubbles that form on skin; one of these is the Tamagawa Hot Spring inSenboku,Akita Prefecture.

Sulphate Onsen: Among the others are acid and sulphate springs, such asZao Onsen in Yamagata. Zao Onsen is one of the most famous and traditional skiing & snowboarding resorts in Japan as well as a popular all year traditional onsen hot spring resort village. What’s better than a soak after a long day of skiing?

Radium Onsen: Radium springs are rarer and usually pricier. Radium Springs are exactly what you’re thinking, if what you’re thinking is slightly radioactive but on a miniscule levels.  The Misasa onsen homes several resorts and spa’s to one of the world’s greatest Radon springs.

Regardless of the Onsen you visit, most importantly remember to throw the towel back and relax.

Check out this off the beaten path hidden hot spring village in Japan!

• Kurokawa Onsen - the hidden hot spring village
• Visit a 1300 year old traditional onsen