Onsens are public baths with water sourced from the hot springs that can be found across the volcanic island of Japan. But that is too simple an explanation for such a wonderful experience. Do not leave Japan without giving these a fair shake. There are just a few simple rules you need to know.

To begin your onsen journey, come prepared. Bring a shower caddy with your favorite soap, shampoo and a washcloth, and bring a towel. Most onsens will provide towels. Many provide soap and shampoo dispensers. You will enter a changing room with lockers, and probably baskets. It's generally safe in Japan to just leave things in the baskets. The lockers can be used though there may be an additional charge for them. In the locker room, you shed your clothes and hopefully any inhibitions you might have about public nudity.

The most important rule, and one you learn to appreciate, is the baths are for soaking only, not cleaning. The cleaning you do beforehand. All onsens will have an area for you to wash and rinse before you enter the bath. The hand held showers will be different than what you may be accustomed to, since the showers may be only about chest high in some places. Small plastic stools are provided for you to sit on as you shower.

Once you're clean and rinsed, it's time to walk from the showers to the baths. Test the waters before you get in! Some are temperate, some incredibly hot, and some absolutely freezing (more on those in a minute). And now.... relax. Everyone's cleaned up before they got in, so you can feel safe sitting down. If you bring a hand towel with you, try not to put the towel in the water. Wring it outside of the water pool and put it either on the rim of the pool or on your head. After enjoying soaking, rinse again and dry as much as you can with the wringed wash towel. Do not go out to the change room dripping wet. It creates a slip safety hazard for you and others. Some people might find it nice to bring a cool bottle of water (encouraged) or beer (discouraged).  Some onsens have vending machines where you can purchase soft drinks and beer.

Depending on the size of the onsen, there may be several baths to try. Feel free to try them all , but do pay attention to any signs next to the pools. While rare, some onsens have electric pools. These are well marked with pictoral symbols, so you won't get in one by accident. If you do find one of these, don't expect to feel it as soon as your feet touch the water. The current come from a rubber mat visible on the walls of the bath; the closer you are to the mat, the stronger the current feels.

If you want to stay longer, but it's just too darn hot, you can try to reset your body temperature by doing the cold plunges. Most onsens have one. Remember, you might be dehydrated from sweating.  Know your limit and physical conditions. Some faint occasionally, especially after drinking beer.

There a huge variety of onsens in Japan, spanning the range from those with several pools, waterfalls, and outdoor tubs, to old one-tub numbers with rusty pipes.  Prices can vary from 200 yen to 2000 yen.  Happy bathing!