Written by Aarohi Narain
Sainokawara Park is a must-visit spot in Kusatsu Onsen, one of Japan’s foremost onsen towns.
Bubbling thermal streams wind through the park, their mineral-rich waters steaming in every season, while stone-lined walking paths lead past hot spring pools, historical monuments, and one of Japan’s largest open-air baths.
Unlike a typical park with lush greenery and shaded benches, Sainokawara boasts the rocky terrain sculpted by centuries of geothermal activity, with hot spring water gushing from the ground in multiple places. The name Sainokawara, meaning “Western Riverbed,” refers to its wide, open landscape, which was once thought to resemble the Buddhist limbo where spirits of the deceased pass through.
Along the trail, you’ll find small spots to dip your hands or feet into the natural hot spring water. Stone Buddhist statues and plaques detail Kusatsu’s onsen folklore.
At the far end of the park lies Sainokawara Rotenburo, one of the largest outdoor onsen in Japan. Spanning around 500 square meters, this expansive open-air bath lets visitors soak in steaming mineral waters while surrounded by nature. Unlike many traditional onsens, Sainokawara Rotenburo allows tattooed guests. Entry costs ¥800. There are bathrooms and cubby holes and storage lockers for your items. You do not need to shower before getting in (there are no showers or soap provided). Mixed bathing takes place on Friday evenings.
