Inazumi Underwater Cave

Inazumi Underwater Cave is a limestone cavern in Bungoōno with sections open to visitors along illuminated paths. The passages reveal rock formations carved by water flow, and water continues to play a significant role in shaping the space.

This limestone cave formed millions of years ago as water seeped through rock and created hollow spaces. A major volcanic event in the region later altered water levels and submerged portions of the passage.

The cave system belongs to the Japan Geopark network and connects to the White Mountain River, recognized among Japan's top 100 water sources.

Most areas are walkable on foot, but some sections can be wet and slippery, so sturdy footwear is helpful. It is worth checking conditions ahead of time, as water levels can vary depending on rainfall and season.

In some spots, visitors can observe rock layers showing different stages of water erosion and how the cave changed over time. This visibility of erosion patterns from separate geological periods offers a rare window into the site's natural history.

Location: Bungoono

GPS coordinates: 32.90009,131.54278

Latest update: December 8, 2025 20:03