Seseki Hot Spring

Seseki is a wild hot spring set right in the rocks on the Shiretoko coast, with no changing room and no shower, so you bathe in the open, mixed with whoever else is there. Twice a day the tide covers the bath completely, and at low tide the family who look after it clears out seaweed and scrubs the rock pool by hand before it's usable again. Because of that there's no fixed bathing schedule, so it's best to check locally or call ahead. The water is hot to the touch, and while there's no set entry fee, visitors are asked to leave a donation in a box on site. Discovered in 1899, the spring has stayed almost exactly this informal for well over a century. It once appeared as a filming location for the TV drama Kita no Kuni kara 2002: Isho, and it's still tended by hand today by a local kombu-fishing family rather than run as a facility.