Guide
Keya no Ooto is one of the largest basalt sea caves in Japan, located along the coast of Itoshima City, Fukuoka Prefecture. Situated within the Genkai Quasi-National Park, it boasts an overwhelming scale with a height of 64m, a depth of 90m, and an entrance width of 10m. The most striking feature is the "basalt columnar jointing"—a geometric formation of hexagonal and octagonal pillars created by nature. This mystical landscape, often cited as one of Japan's three great basalt caves, offers a sense of awe and wonder to all who visit.
This sea cave was formed over countless years through the relentless erosion of ocean waves against basalt rock. The well-developed columnar jointing makes it a geologically significant and precious site. The surrounding area is protected as part of the Genkai Quasi-National Park, ensuring the preservation of its rich natural environment. Historically, it has been a place to admire the sublime beauty of nature, and today, a well-maintained sightseeing boat route allows visitors to explore its mysterious depths.
The ultimate highlight is the experience of sailing into the heart of the cave via a sightseeing boat. From the water, you can witness the massive rock walls and the rhythmic beauty of the columnar joints up close—a perspective that is impossible to experience from the land. The contrast between light and shadow near the cave entrance, combined with the sound of the waves, creates a powerful, sensory experience. Additionally, the stunning coastline and the vibrant contrast between the blue sky and the sea make this an exceptional spot for photography enthusiasts.
The sightseeing boat typically operates from mid-March to late November. For the best views, we recommend visiting between late morning and early afternoon when the weather is stable and the sea is calm. During the summer, you can enjoy a refreshing cruise accompanied by a cool sea breeze and crystal-clear waters. Please note that cruises may be canceled due to bad weather or high waves, so we highly recommend checking the weather forecast before your visit to ensure a smooth trip.
The primary activity in this area is the "Keya no Ooto Sightseeing Boat" cruise, departing from Keya Fishing Port. Navigating through the cave feels like traveling through a living piece of natural art. Beyond the cave, the nearby Keya Beach offers a perfect setting for swimming in clear waters and enjoying family leisure activities. It is a wonderful place to combine the awe of natural formations with a relaxing day by the sea.
Very close to the cave is Keya Beach, known for its shallow waters and high transparency. It is selected as one of the "100 Best Beaches in Japan," making it a popular destination for families and beachgoers. The entire Itoshima area is a highly popular driving destination, offering beautiful coastal roads lined with trendy cafes and local gourmet-focused restaurants. It is the perfect destination for a trip that combines nature, relaxation, and culinary delights.
For your safety while on the boat, please wear comfortable and practical clothing. We recommend bringing a hat, sunglasses, and sunscreen to protect yourself from the sun and sea breeze. Please prepare cash in advance, as some boat operators may require cash payments. To protect this precious natural environment, please follow local etiquette by taking all trash home with you and respecting the natural surroundings.