Yonaguni Monument
The Underwater Ruins, a popular diving spot in Yonaguni, Japan, were discovered in 1986 by a local diver. Along with the fascinating hammerhead sharks, divers can explore the ruins located just 15 minutes away from the port. These ruins feature a massive staircase-shaped wall stretching approximately 250m east-west and 150m north-south. The underwater site offers exceptional visibility of 25m and a maximum depth of 22m.
Divers with advanced or expert level skills can enjoy spotting hammerhead sharks and encountering various species of vibrant reef fish. It is worth noting that although the water depth is shallow, caution is necessary due to occasional fast currents. The true origins of the ruins remain debated, leaving an air of mystery. The site showcases numerous vertical rocks, resembling stairways, passageways, and stages, creating a captivating atmosphere.
Exploring this unique dive site provides divers with the opportunity to explore notable spots like "Castle Gate," "Main Terrace," "Bifurcated Rock," and "Turtle Monument." The sheer sight of these intriguing formations is enough to immerse oneself in the wonder of the underwater world.
For divers seeking an unforgettable adventure, the Underwater Ruins in Yonaguni, Japan, offer a remarkable and captivating dive experience.
Divers with advanced or expert level skills can enjoy spotting hammerhead sharks and encountering various species of vibrant reef fish. It is worth noting that although the water depth is shallow, caution is necessary due to occasional fast currents. The true origins of the ruins remain debated, leaving an air of mystery. The site showcases numerous vertical rocks, resembling stairways, passageways, and stages, creating a captivating atmosphere.
Exploring this unique dive site provides divers with the opportunity to explore notable spots like "Castle Gate," "Main Terrace," "Bifurcated Rock," and "Turtle Monument." The sheer sight of these intriguing formations is enough to immerse oneself in the wonder of the underwater world.
For divers seeking an unforgettable adventure, the Underwater Ruins in Yonaguni, Japan, offer a remarkable and captivating dive experience.
Diving Conditions Score for Yonaguni Monument
7.5
GoodGood diving conditions!
The score is based on a calculation of the current weather and sea conditions.
Dive Site Overview for Yonaguni Monument
Depth
22m
Visibility
25m
Experience Level
advanced
expert
Weather Conditions for Yonaguni Monument
Wave Height
1.14m
Wind Speed
27.2 m/s
Water Temp
28.5°C
Visibility
29.32km
Cloud Cover
46%
Wave Period
4.85s
Air Temperature
29.2°C
Precipitation
0 mm
Detailed 7-Day Diving Forecast for Yonaguni Monument
Alpha
Dive Score Chart for Yonaguni Monument
Best time to dive: 16:00 with score 6.6718/10. Water conditions: Waves 1.14m, Wind 26.8 m/s.Best night dive time: 3:00 with score 6.2041/10.
Chart showing hourly dive conditions including wave height, wind speed, water temperature, and visibility throughout the day.
Sunrise at Yonaguni Monument: 06:00
Sunset at Yonaguni Monument: 18:00
Optimal diving conditions at Yonaguni Monument are affected by daylight hours. Sunrise occurs at 06:00 and sunset at 18:00, which impacts visibility and water temperature for scuba diving and snorkeling.
Best Overall
16:00Score: 6.7/10
Waves: 1.14m (4.85s), Wind: 26.8 m/s
Safest Overall
14:00Score: 6.7/10
Waves: 1.14m (4.85s), Wind: 27.2 m/s
Best Night
3:00Score: 6.2/10
Waves: 1.14m, Wind: 27.3 m/s
Seasonal Analysis for Yonaguni MonumentAlpha
Historical patterns and best seasons for diving at Yonaguni Monument
The dive score combines all factors to rate overall diving conditions throughout the year. Higher scores indicate better diving conditions.
Monthly Dive Score Analysis - Seasonal Diving Conditions
Higher values indicate better diving conditions
Seasonal DiveScore Chart
This chart displays monthly diveScore data throughout the year, showing seasonal patterns. The data is presented as a bar chart with an overlaid line graph.Dive scores range from 1 to 10, with 10 being optimal conditions.
Higher values indicate better diving conditions
Best Season for Yonaguni Monument
Winter
Avg. Score: 8.3/10
Winter offers the best overall diving conditions with calmer seas and better visibility, despite cooler temperatures.
Best Months for Yonaguni Monument
January
Score: 8.4
November
Score: 8.4
March
Score: 8.3
Ideal Conditions for Yonaguni Monument
Water Temp
28.1°C / 82.6°F
June
Visibility
12.0m / 39.4ft
July
Wave Height
2.9m / 9.5ft
March
Wave Period
8.0s
January
Seasonal Insights for Yonaguni Monument
Yonaguni Monument shows typical northern hemisphere patterns with July being the warmest month (29.0°C) and January the coldest (16.5°C). The calmest conditions typically occur in March with average wave heights of 2.9m and wave periods of 8.0s. The most comfortable wave conditions are in March with a low wave steepness ratio, creating gentler swells. January offers the longest wave periods (8.0s), creating more comfortable and predictable conditions for boat entries and exits. Ocean currents are slowest in January (0.5m/s) and strongest in January (0.5m/s). July is usually the driest month with 0.0mm of precipitation. For beginners, the best time to visit would be during March to May, when ocean conditions are calmer with long-period waves and currents are typically weaker. Experienced divers might enjoy the challenges and potentially better visibility during the shoulder seasons, with moderate currents that can improve marine life encounters.
Last updated: 1 min. ago - Jun 18, 2026
Note: This dive site is not a verified dive site. Please dive with caution. This dive site might have incorrect information by the community.
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