Keya no Oto

芥屋の大門

Nature & Caves · Fukuoka

Located at Cape Oto on the northwestern tip of the Itoshima Peninsula, Fukuoka Prefecture, Keya no Oto is one of Japan's three largest basalt caves, carved by the Genkai Sea into towering hexagonal and octagonal columnar rock formations. Designated a National Natural Monument, the cave rises 64 meters high, stretches 90 meters deep, and is only accessible by sightseeing boat from Keya Fishing Port between March and November. A short coastal hike also leads to a clifftop viewpoint overlooking the cave and the surrounding Genkai Quasi-National Park.

TikTok video of June 14, 2026