Koshimizu Onsen

Koshimizu Onsen is situated in Koshimizu, a coastal agricultural town in the Okhotsk Subprefecture of northeastern Hokkaido, facing the Sea of Okhotsk along a distinctive lagoon coastline where the shallow Lake Notoro (Notoro-ko) is separated from the open sea by a narrow sand bar, creating a habitat celebrated for its spring bloom of Siberian iris (Kosaho) that carpets the lagoon shores in purple and lavender when the winter ice retreats. The coastal marshes here are important stopover sites for migratory shorebirds and waterfowl, and in winter the ice floes of the Okhotsk drift ice can be observed from shore. The onsen provide mineral bathing with views toward the icy Okhotsk waters, offering a warm refuge from Hokkaido's most severe northern climate in a farming community where flower blooms, drift ice, and migratory birds mark the passage of the seasons with vivid natural drama.