Iyo Nagahama Onsen

Iyo Nagahama Onsen is located in Iyo city on the coast of Ehime Prefecture facing the Seto Inland Sea on Shikoku, where chloride-rich thermal waters draw from geothermal sources to provide mineral bathing with views of the island-studded inland sea in one of Japan's most historically maritime landscapes. The sodium-chloride mineral composition of these hot springs is valued in Japanese onsen culture for its deeply warming, skin-conditioning, and circulation-enhancing properties, particularly appreciated on this coastline where the Seto Inland Sea's mild climate and seafaring heritage have shaped the local culture for millennia. Iyo's position along the Seto Inland Sea coast—facing the ancient sea routes connecting Kyushu, Shikoku, and Honshu that were fundamental to Japanese maritime history and trade—gives this coastal onsen a setting that connects thermal bathing with one of Japan's most historically significant marine landscapes.