Kussharo Kohan Iso-no-yu

A large, pond-like open-air bath right on the shore of Lake Kussharo, fed by hot spring water rising at the lakeside. The basin is mixed (konyoku, 混浴) and swimwear is allowed; there are simple separate changing sheds on either side. The water runs around 38°C, comfortable for long soaks, especially in summer or with snow falling around you in winter. Free and open around the clock, though algae on the bottom can make it slippery.