Shima-keya, Itoshima, Fukuoka
Rating
Cost per person
¥2,500
Keya no Oto, also known as Keya no Omoto, is Japan's largest basalt cave and a designated natural monument. Located in Itoshima, Fukuoka, it's accessible by bus from JR Chikuzen-Maebaru Station, followed by a short walk. While land access to the cave itself is limited, you can take a sightseeing boat from the harbor for a closer view. The surrounding area offers scenic spots like Totoro Forest and an observation point with panoramic coastal views. Note that the trails can be steep and slippery, so wear appropriate footwear. Visit during calmer weather for the best boat tour experience.