Yokoya Onsen is a hot spring town in Nagano, Japan. The water leaves the ground at 19°C, cool enough that the baths here are usually reheated. Officially the water is classed as carbon dioxide spring and iron spring. Its sources put out around 1,080 litres a minute. 1 inns take visitors here.
Fine bubbles cling to your skin. Rare in Japan, and usually cooler than other springs.
Turns reddish brown as the iron meets air. The water is clear at the source.
Figures from the town's Japanese Wikipedia article.
36.0364, 138.2758 — open the map
Planning a first soak? Read how an onsen stay works, and what to do if you have tattoos.