The Inazumi Underwater Limestone Caves in Oita Prefecture are the largest series of underwater limestone caves in Japan. The caves were formed 300 million years ago and were once completely submerged, however, now the upper parts are exposed to air due to erosion.
Located at the foot of Mount Inazumi, a drainage channel was made allowing tourists to visit the cave. Some of the stalactites are partially underwater, which creates a mysterious world where the underwater world reflects the world above.
With more than twenty caverns in the system and a dozen or so stalactites, viewing this natural underwater marvel is made easier thanks to the nearby hotels, restaurants, and attractions on offer. The cool internal temperature inside the caves makes for a nice retreat no matter the time of year.
20 minutes by car from Miemachi Station.