Iokido Cave

Ioki-dou

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A mystical cave formed by the sea approximately 3 million years ago. The cave stays at a cool 20 degrees Celsius year-round, and offers stunning valley views with lush fern growth.

Historic Sites
Scenic Views

Tourist destination images of Iokido Cave(1)

Tourist destination images of Iokido Cave(2)

Tourist destination images of Iokido Cave(3)

HighlightsA mystical cave formed by the sea approximately 3 million years ago
Cave interior maintains a cool 20 degrees Celsius year-round
Stunning valley views with lush fern growth
Nationally designated fern colony
Experience a feeling of stepping back in time

Basic Information

Address: 117 Iogi, Aki City, Kochi Prefecture Search for tourist attractions in Kochi

Access: 7-minute walk from Iogi Station on the Gomen-Nahari Line Approximately 60-minute drive from Kochi Station Show route

Op.Hours: 8:30 AM to 5:00 PM (Last entry 4:30 PM)

Cld.Days: Open every day

Fee: Free admission

INFO: We recommend wearing comfortable athletic shoes or hiking boots for walking around. (During prolonged rainy periods or the day after heavy rain, rubber boots are recommended.) Also, sandals are not recommended in summer as there is a possibility of encountering snakes, such as mamushi.

HP: https://www.attaka.or.jp/kanko/dtl.php?ID=8003

Overview

Iokido Cave, located in Iogi, Aki City, Kochi Prefecture, is a natural cave formed by the uplift of sedimentary layers (Anauchi Formation) deposited in the sea approximately 3.1 to 2.3 million years ago (Pliocene to Pleistocene). The cave maintains a constant temperature of around 20 degrees Celsius throughout the year, measuring approximately 40 meters long, 3 meters wide, and 5 meters high. Beyond the cave lies a cliff-enclosed area boasting a mystical sight of thriving ferns. Designated a national natural monument on October 20, 1926, the Iokido Cave area is surrounded by abundant nature, perfect for hiking and camping. The cave offers cool, refreshing air even in summer. Exiting the cave and entering the valley reveals a breathtaking mystical landscape of lush green ferns, making you feel as if you've stepped back in time. The nationally designated fern colony houses a diverse array of fern species, creating a truly awe-inspiring sight. Iokido Cave is a highly recommended tourist spot for experiencing the wonders of nature.