5 facilities matching "Nature-Immersion Onsen & Sauna" in Nagano. Compare amenities, setting and access to find the right spot for your trip. Open-air baths that dissolve into the forest. Cold plunges drawn from mountain streams. We curate ryokan, onsen hotels and day-use bathhouses where bathing and the surrounding nature feel inseparable — a deep forest-bathing experience layered with the onsen and sauna ritual, whether you stay overnight or visit just for the day.