Japan's Largest Underwater Cave - Inazumi Underwater Cave

Inazumi Underwater Cave

About Inazumi Underwater Cave

Inazumi Underwater Cave is a limestone cave located in Bungo-ono City, Oita Prefecture.

The underwater limestone cave, formed about 300 million years ago, is a rare sight. It's estimated that it was submerged by the eruption of Mt. Aso 300,000 years ago and became what it is today. The total length of the discovered area is more than 1km, and is the largest underwater limestone cave in Japan. There are still unknown areas to be discovered.

The cave is lit up by LEDs in some places, giving it a mysterious atmosphere. The area  illuminated by blue light is especially beautiful. 

Blue light

Visiting the cave

The temperature inside the cave is 16 degrees Celsius all year round. Since the summers are cool and the winters are warm, you can see the wonderful underwater limestone cave all year round.

You can enjoy a walking exploration,  scuba diving and a tent sauna.

Visit the cave and let its negative ions heal your mind and body. 

Cave passageway