Tidal hot spring
Perched on the rocky shoreline of southern Hokkaido’s Shimokita Peninsula, Mizunashi Kaihin Onsen is a rare tidal hot spring where natural baths emerge only during low tide. With views of the Tsugaru Strait and, on clear days, even Honshu across the water, this open-air seaside onsen offers a raw, elemental experience—completely free and set directly on the coast. There are no changing rooms or amenities, making it best for adventurous travelers seeking something off the beaten path.
