About
Keya no Oto sea caves showing the distinctive hexagonal basalt columnar joints carved by the Genkai Sea, Itoshima, Fukuoka, Japan. Image from Wikimedia Commons (CC BY-SA 3.0)
Keya no Oto (芥屋の大門) is Japan's largest basalt sea cave, designated as a National Natural Monument in 1966 and located within the Genkai Quasi-National Park at Cape Oto on the northwestern tip of the Itoshima Peninsula. The site combines two distinct experiences: a boat tour into the spectacular 64-meter-high basalt cave featuring hexagonal columnar joints, and a magical forest trail known locally as "Totoro Forest" (Totoro no Mori) leading to an observation deck with panoramic coastal views. 🔗
The cave's extraordinary dimensions—64 meters in height, 90 meters in depth, and 10 meters in entrance width—make it the largest basalt cave in Japan. Over millennia, the relentless waves of the Genkai Sea have carved the weak portions of the volcanic rock, creating rows of hexagonal and octagonal basalt columns so geometrically precise they appear almost artificial. 🔗
Cultural & Religious Significance
The basalt formations represent ancient volcanic activity, with the hexagonal structures forming as lava cooled and contracted uniformly. The site's nickname "Totoro Forest" references Studio Ghibli's "My Neighbor Totoro" and captures the magical atmosphere of the camellia tree-lined trail. The path winds through wild camellia trees whose leaves have grown into distinctive dome shapes due to constant sea breezes, creating a tunnel-like effect reminiscent of the enchanted forest from the film. 🔗
The roughly-cleared trail is covered almost entirely by camellia branches, creating a fantasy atmosphere with dappled shadows. After approximately 5 minutes of climbing, hikers emerge onto a small wooden observation platform with fantastic views of the deep blue Genkai Sea, the coastline, and the opposite side of the cave cliffs. 🔗
Visiting Information
Boat Tour Operating Period: Mid-March through end of November (weather dependent)
Daily Boat Schedule:
- Weekdays: 9:30 AM - 4:15 PM (departures every 45 minutes)
- Weekends/Holidays: 9:30 AM - 4:30 PM (departures every 30 minutes)
- Important: Tours subject to cancellation based on sea conditions. Call ahead (092-328-2012) to confirm availability. 🔗
Admission:
- Boat Tour: Adults ¥1,000, Children (3 years-elementary) ¥500
- Totoro Forest Trail: Free access
- Tour duration: Approximately 25 minutes
- No advance reservations required 🔗
Access from Itoshima Retreat House:
- By car: Approximately 15 minutes drive along scenic coastal route
- Parking: Free parking available at both boat pier and trail areas
Public Transportation:
- From JR Chikuzen-Maebaru Station: Showa Bus "Keya Line" to "Keya" stop (26-30 minutes, ¥200)
- From bus stop: 10 minutes walk to boat pier/trail 🔗
Contact: Keya Oto Tourism Association: 092-328-2012
Current Status: Open and operational. Tours weather-dependent.
The Experience
Boat Tour Experience
The 25-minute boat tour from Keya Fishing Port offers intimate views of the 64-meter-high basalt columns rising from the churning Genkai Sea. The hexagonal and octagonal columnar joints create mesmerizing geometric patterns. If sea conditions permit, the boat ventures inside the cave—an extraordinary experience surrounded by the echo of waves and dramatic darkness punctuated by the cave opening. The contrast between the cave's "black mouth" and the clear blue sea creates a powerful sight. 🔗
Totoro Forest Trail Experience
The 800-meter trail provides a contrasting experience—intimate and enclosed rather than open and grand. The path follows a single route upward through the camellia tree tunnel, creating a sense of journeying through a magical realm. The trees' dome-shaped canopies filter sunlight into dappled patterns across the path.
Trail Characteristics:
- Distance: Approximately 800 meters one way
- Elevation Gain: Moderate stairs to observation deck
- Time: 5 minutes upward; 10-15 minutes leisurely round trip
- Difficulty: Beginner-friendly, suitable for families
- Trail Surface: Natural with cleared paths and steps 🔗
The Observation Deck: The small wooden platform offers panoramic views:
- The opposite side of the Keya no Oto cave cliffs
- Full sweep of the Genkai Sea coastline
- Deep blue ocean extending to horizon
- Surrounding coastal landscape including Nigi no Hama Beach
- Excellent photography opportunities 🔗
Practical Visiting Tips
November 1-2, 2025 Considerations
Seasonal Advantages:
- Clear photography conditions with 14.8 hours sunshine per day
- Comfortable hiking temperatures (17°C highs, 11°C lows)
- Last opportunity for boat tours before winter closure
- Lower crowds than summer season
- Excellent sea visibility with 71% humidity 🔗
Weather Preparations:
- Bring light sweater/windbreaker for coastal breezes
- Sea breezes stronger at observation deck
- Low rain possibility (23%) but pack light rain layer
Photography Conditions:
- Morning light (9:30-11:00 AM) provides excellent side-lighting on basalt columns
- Clear November days offer strong contrast between dark basalt, white foam, and blue sea
- Forest trail benefits from autumn sun creating dramatic shadows
- Observation deck faces north/northwest with good lighting throughout day
Best Photo Spots
Boat Tour:
- Hexagonal column close-ups
- Cave entrance from sea level
- Panoramic coastal views
- Interior cave shots (if conditions permit)
Totoro Forest:
- Tunnel entrance with torii gate
- Mid-trail looking back down the camellia tunnel
- 360-degree views from observation deck
- Aerial perspective of forest canopy
Photography Tips:
- Wide-angle lens for cave interior and forest tunnel
- Telephoto captures basalt hexagonal pattern details from deck
- Polarizing filter enhances blue sea and reduces glare
- Fast shutter speed for boat shots due to wave motion
Visitor Strategies
Timing:
- First boat departure (9:30 AM) has fewest passengers
- Early morning preferred for photography and sea conditions
- Totoro Forest rarely crowded; most visitors focus on boat tour
- November already represents low-season visiting
Safety Considerations:
- Always call ahead (092-328-2012) to confirm boat tour availability
- Sea sickness possible on rougher days
- Boat has safety equipment but no English safety briefings
- Spray possible—protect cameras and electronics
Trail Safety:
- Stairs can be uneven; watch footing on descent
- Observation deck railings present but be cautious near edges
- Strong winds possible at deck; secure hats and light items
- Wear closed-toe shoes with good traction
Nearby Attractions:
- Keya Beach (adjacent): White sand beach, walking distance from boat pier
- Nigi no Hama Beach (adjacent): Bow-shaped coastline with stunning views
- Mount Tateishi (nearby): Beginner-friendly hiking trail, 30 minutes from peak parking
- Sakurai Futamigaura (15 minutes drive): Famous "wedded rocks" with sacred rope 🔗
Location: View on Google Maps
Source: attractions/itoshima/keya-no-oto-park.md