Do I need to bring anything to bathe at Yubara Onsen Sunayu?

You must bring swimwear as bathing suits are mandatory in this mixed-gender facility. Bring your own towels as well. The open riverside location requires all visitors to wear appropriate swimwear.

Is Yubara Onsen Sunayu safe for children and families?

Yes, the facility is family-friendly and welcomes children. Parents should supervise children as water depth and temperature vary throughout the bathing area and the riverbed can be uneven.

How do I control the water temperature at Sunayu?

Dig into the sandy riverbed to adjust temperature—deeper digging exposes hotter water from the spring source at around 50 degrees Celsius. Moving closer to or farther from the river current also changes the temperature.

Are there changing facilities and other amenities at Sunayu?

Basic changing facilities are available, but amenities are minimal. There are no lockers, showers, or elaborate facilities. For comprehensive amenities including indoor baths and dining, stay at nearby ryokan inns in Yubara Onsen town.

Can I bathe at Sunayu if I have tattoos?

Yes, tattoos are generally not restricted at Sunayu since it is an outdoor, swimwear-required facility rather than a traditional indoor onsen. However, confirm current policies before visiting as rules can vary.

Yubara Onsen Sunayu

4.2 (672)Public BathSpaPoint Of InterestEstablishment

Last updated Apr 22, 2026

Yubara Onsen Sunayu is a unique natural hot spring located in Maniwa City, Okayama Prefecture, nestled along the Asahi River. This open-air bathing facility sits directly in the riverbed, where hot spring water naturally bubbles up through the sand and mixes with the cool river water, creating a one-of-a-kind bathing experience. The name "Sunayu" literally translates to "sand bath," referring to the distinctive sandy bottom where bathers can dig to adjust the water temperature to their preference.

The hot spring has a history spanning over 800 years and is known for its therapeutic alkaline waters with a pH of approximately 9.0, which are said to benefit skin conditions and promote overall relaxation. The spring became particularly famous after the construction of the Yubara Dam in 1955, which partially submerged the original hot spring town. The current Sunayu facility was reconstructed downstream and has become an iconic symbol of the region's onsen culture.

Visitors experience the unusual sensation of bathing in an open-air riverside setting where the water temperature varies depending on location and depth. Bathers can dig into the sandy riverbed to find their ideal temperature, as the hot spring water emerges at around 50 degrees Celsius before blending with the cooler river water. The bathing area is mixed-gender and requires swimwear, making it accessible for families and groups. The facility operates year-round, though river conditions may occasionally affect access during periods of heavy rainfall or flooding.

Yubara Onsen Sunayu is located approximately 50 kilometers north of Okayama City. Visitors can reach the area by taking the JR Hakubi Line to Chugoku-Katsuyama Station, followed by a 25-minute bus ride on the Maniwa Kotsu bus bound for Yubara Onsen. By car, the journey from Okayama takes roughly 90 minutes via Route 313.

What other travelers are saying about Yubara Onsen Sunayu

We visited Yubara Onsen Sunayu during winter when it was -2°C — such a magical experience! My husband and my daughter soaked in the warm natural hot spring pond, and the contrast between the cold air and the hot water felt incredible. It’s an unforgettable and truly special moment! ❤️❄️☃️

Alya Syafina

Oct 4, 2025

This is a nice, peaceful natural hot spring that offers a unique experience for visitors. Women have the option to wear clothing while enjoying the hot spring, which is a thoughtful touch. Plus, there are many signs asking one to cover up, with towel or some clothes. However, don’t be surprised if you see many men, both young and old, walking around naked, with only a small piece of cloth to cover their private parts. The water in the hot spring is quite hot, probably around 42°C or higher. Inside the hot spring, there’s some moss, which seems harmless—nobody seemed to mind. I took a dip and didn't experience any allergies, but enter at your own risk. There are clean water sinks available to wash yourself afterward and also a sauna room to change your clothes. The sauna was not in service and hence, I changed comfortably there. This place is very local, with hardly any tourists.

Love this place!

I visited on December 30, 2025, taking the Maniwa City community bus "Maniwa-kun" from Chugoku Katsuyama Station. It's recommended by many hot spring writers, so it was definitely something I wanted to visit. It has a very different feel from Kawayu Hot Springs in Misasa Onsen, also in the Chugoku region. I was impressed by how large and well-maintained it is. Bathing attire and a swimsuit are recommended, and although I later realized I should have brought one, I wish I had. There were quite a few foreign visitors there, too. The water is an alkaline simple spring, with a source temperature of around 45°C and a pH of 9. It's said to be good for skin, as it removes dead skin cells. It's best to be careful of heat shock in the winter.

Sand bath! I went to the famous Yubara Onsen Sand Bath in Okayama Prefecture. I thought it would be crowded during the day, so I visited at 2am. I was grateful that it's open 24 hours a day. As expected, there was no one there at this time, so I was able to relax and enjoy the bath. It was dark and hard to see, but it turns out to be a fairly large bath. It was a cold time of year in late November, but the temperature was just right - neither too hot nor too cold. It's a mixed bath, but I felt that women needed courage. It was a great hot spring that was free to use 😊