Explore One of Japan's Three Greatest Limestone Caverns and the Dragon Blue Underground Lake
About this spot
One of Japan's three greatest limestone caverns, alongside Akiyoshi Cave and Ryuko Cave, it is designated as a National Natural Monument as the "Iwai Gushing Cavern and Bat Habitat." The known total length exceeds 4,000 meters, with approximately 700 meters open to the public. The greatest attraction is its underground lake, renowned worldwide for its exceptional transparency. Lit by electric lights, the water surface glows with a deep blue called "Dragon Blue," captivating the eye with its mesmerizing beauty. In the 3rd underground lake with a depth of 98 meters, you can even see bands of light descending to the bottom. The cave maintains a temperature of around 10°C year-round, making it a pleasant natural cooling chamber during summer explorations. With steep stairs known as the Mihara Pass, you and your friends can enjoy an exhilarating full-scale underground expedition while cheering each other on.
Tips
About 1 hour 40 minutes by car from Morioka Station; you can also access it via JR Bus Iwaizumi Ryusen Cave Line. The cave floor is wet and slippery, so wear comfortable hiking shoes. Bring a jacket even in summer. A backpack with both hands free is recommended due to steep stairs. Your entrance ticket is a combined ticket with Ryusen Shinado Science Museum across the street—keep it safe.
Best time to visit
Approximately 60-90 minutes. The cave is quietest early morning after opening, when you can peacefully admire the blue underground lake.
Access & map
1-1 Kaminarinari, Iwaizumi, Shimohei District, Iwate 027-0501
Model course featuring this spot
Ryusen Cave (龍泉洞) - Dragon Blue Underground Lake Exploration
Iwate
Explore features & model courses
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