Tsuna Onsen is a thermal spa facility in the northern Awaji district of Awaji Island, enjoying the elevated sea views and pastoral landscapes that define this agricultural heart of the Seto Inland Sea. The mineral waters offer warm, restorative bathing within sight of the Akashi Strait, where fast-moving tidal currents have shaped the island's fishing culture and cuisine—particularly its celebrated sea bream and sea vegetables. Awaji Island's role as a birthplace of Japanese civilization in Shinto mythology infuses even a simple soak here with a quiet sense of ancient significance.
Insider tip — Tsuna Onsen on Awaji Island's western coast offers silica-enriched waters prized for their beautifying properties, with outdoor baths that face directly toward the Seto Inland Sea at 42°C. The modest, community-oriented facilities retain a local authenticity rarely found at more commercialized island destinations. The surrounding area is dotted with flower parks and scenic coastal roads ideal for cycling between spa stops. Sunset bathing in an outdoor rotemburo overlooking the glowing Seto sea is an experience that lingers long after you leave.
