Immerse yourself in the serene ambiance of Inazumi Limestone Cave,  in Kyushu, Japan, where visitors can enjoy a tent sauna then soak in the limestone cave water bath where the therapeutic aura of negative ions permeates, offering solace and rejuvenation for both body and mind.

The Inazumi Underwater Limestone Cave, situated in Oita Prefecture, represent Japan's most extensive network of submerged limestone caverns. Within this natural wonder, a crystal-clear stream flows in mesmerizing shades of blue and emerald. Alongside the primary limestone cave, visitors can explore the largest Guanyin statue in Oita and the Cave Archives Center. Moreover, Inazumi is renowned for its firefly sightings, with a captivating firefly festival held toward the end of May.

The Submerged Stalactite of Inazumi claims the title of Japan's largest water stalactite cave, nestled upstream of the Hakusan River, a member of the prestigious 100 national famous clear streams. This remarkable cavern boasts an abundance of stalactites and reaches depths exceeding 40 meters.

Originating in the Paleozoic Era some 300 million years ago, the Inazumi Underwater Limestone Cave underwent transformation around 300,000 years ago due to the eruption of Mt. Aso, shaping it into its current form. The cave is a unique spectacle worldwide, featuring a profusion of underwater stalactites, coral stones, bellholes, and helictites.

Innumerable stalactites and abyssal chasms beyond 40 meters in depth, combined with the ceaseless flow of pristine waters from hidden recesses, create a captivating panorama within the underwater limestone cave. Its ever-evolving beauty presents a captivating contrast, transporting visitors into a realm of fantasy.

The cave maintains a year-round temperature of 16 degrees Celsius (60.8 degrees Fahrenheit), providing a comfortable environment that offers cool respite in summer and cozy warmth in winter. This allows visitors to marvel at the magnificent underwater limestone cave at any time of the year.