What Is an Onsen?
An onsen (温泉) is a natural hot spring bath fed by geothermally heated water. Japan sits on the Pacific Ring of Fire, which means geothermal activity is abundant — and so are hot springs. The practice of bathing in onsen dates back over a thousand years and remains deeply embedded in Japanese daily life and leisure culture.
Visiting an onsen is one of the most rewarding experiences you can have in Japan. But the unwritten rules of onsen etiquette can feel intimidating. This guide walks you through everything you need to know.
Types of Onsen
- Rotenburo: Outdoor baths, often set in stunning natural surroundings — mountains, forests, or seaside cliffs.
- Uchiyu: Indoor baths, common in hotels and public bathhouses (sento).
- Kashikiri-buro: Private, reservable baths — ideal for those uncomfortable with communal bathing.
- Konyoku: Mixed-gender baths, now rare but still found at some traditional hot spring towns.
The Rules: What to Do
- Wash thoroughly before entering. Every onsen has a washing area with small stools, showerheads, and soap. You must wash your entire body before getting into the communal bath. This is non-negotiable.
- Bring a small towel. A tenugui (small cotton towel) is typically provided or available to purchase. You can use it to wash and to cover yourself modestly while walking around — but it must not enter the water.
- Enter slowly. The water is hot — often between 40°C and 45°C (104–113°F). Lower yourself in gradually to let your body adjust.
- Stay hydrated. Drink water before and after bathing. Avoid alcohol before a soak.
- Speak quietly. Onsen are spaces of relaxation. Keep voices low and phones away.
What NOT to Do
- Do not bring your towel into the bath water. It goes on your head or is left at the side.
- Do not wear a swimsuit in traditional onsen — you bathe unclothed. (Some tourist-oriented facilities now allow swimwear; check ahead.)
- Do not take photos inside the bathing area — ever.
- Do not dye your hair immediately before visiting — residual dye can contaminate the water.
- Do not submerge your head.
Tattoo Policies
Many traditional onsen in Japan prohibit guests with visible tattoos from entering communal baths. This policy stems from historical associations between tattoos and organized crime, though attitudes are slowly changing. If you have tattoos, look for onsen that are tattoo-friendly (some actively advertise this), or book a private kashikiri-buro where the rules are more flexible.
Best Onsen Destinations in Japan
| Destination | Prefecture | Known For |
|---|---|---|
| Hakone | Kanagawa | Views of Mt. Fuji, proximity to Tokyo |
| Beppu | Oita | "Hells" (jigoku) hot springs, high spring volume |
| Kinosaki Onsen | Hyogo | Seven public bathhouses, yukata culture |
| Noboribetsu | Hokkaido | Volcanic scenery, diverse spring types |
| Kusatsu | Gunma | High-quality acidic waters, yumomi ceremony |
Go in with an open mind, respect the rules, and the onsen experience will become one of your most treasured memories of Japan.