Kohamajima Island
Welcome to this small island in the east of Iriomote Island, just 16km in circumference. Here, you'll find a luxury resort hotel that offers a perfect retreat for divers. Situated between this island and Iriomote Island lies the breathtaking Yonara Waterway. Immerse yourself in a vibrant underwater world teeming with approximately 400 colorful coral species, including exquisite table coral and eda coral. The tropical fish species found here are truly mesmerizing. Dive enthusiasts will be thrilled to know that the Yonara Waterway boasts several renowned spots where unforgettable encounters with majestic manta rays await.
One of the highlights of this dive site is a stunning cluster of Ryukyukicka coral. As you explore its depths, keep an eye out for eels, scorpionfish, and the formidable giant scorpionfish that preys upon them. Springtime brings about lively bobwhite spawning events, adding a touch of natural wonder to your diving experience.
Visibility at this site reaches an impressive 21 meters, providing excellent underwater views. With a maximum depth of 18 meters, both beginner and advanced divers can indulge in the beauty of this underwater paradise. Located in Japan's Okinawa Prefecture, this dive site is conveniently close to Kohama, Taketomi, and Yaeyama.
Come and discover the captivating wonders of this dive site. Whether you're an experienced diver seeking thrilling encounters or a beginner eager to explore, this Japanese gem promises an unforgettable underwater adventure.
One of the highlights of this dive site is a stunning cluster of Ryukyukicka coral. As you explore its depths, keep an eye out for eels, scorpionfish, and the formidable giant scorpionfish that preys upon them. Springtime brings about lively bobwhite spawning events, adding a touch of natural wonder to your diving experience.
Visibility at this site reaches an impressive 21 meters, providing excellent underwater views. With a maximum depth of 18 meters, both beginner and advanced divers can indulge in the beauty of this underwater paradise. Located in Japan's Okinawa Prefecture, this dive site is conveniently close to Kohama, Taketomi, and Yaeyama.
Come and discover the captivating wonders of this dive site. Whether you're an experienced diver seeking thrilling encounters or a beginner eager to explore, this Japanese gem promises an unforgettable underwater adventure.
Diving Conditions Score for Kohamajima Island
6.9
Above AverageDecent conditions, proceed with caution.
The score is based on a calculation of the current weather and sea conditions.
Dive Site Overview for Kohamajima Island
Depth
18m
Visibility
21m
Experience Level
beginner
advanced
Weather Conditions for Kohamajima Island
Wave Height
1.46m
Wind Speed
22.3 m/s
Water Temp
28.1°C
Visibility
9.48km
Cloud Cover
100%
Wave Period
5.45s
Air Temperature
27.2°C
Precipitation
0.3 mm
Detailed 7-Day Diving Forecast for Kohamajima Island
Alpha
Dive Score Chart for Kohamajima Island
Best time to dive: 17:00 with score 6.636333333333334/10. Water conditions: Waves 1.44m, Wind 21 m/s.Best night dive time: 18:00 with score 6.263333333333334/10.
Chart showing hourly dive conditions including wave height, wind speed, water temperature, and visibility throughout the day.
Sunrise at Kohamajima Island: 06:00
Sunset at Kohamajima Island: 18:00
Optimal diving conditions at Kohamajima Island 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
17:00Score: 6.6/10
Waves: 1.44m (5.55s), Wind: 21 m/s
Best Night
18:00Score: 6.3/10
Waves: 1.46m, Wind: 22 m/s
Seasonal Analysis for Kohamajima IslandAlpha
Historical patterns and best seasons for diving at Kohamajima Island
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 Kohamajima Island
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 Kohamajima Island
January
Score: 8.5
November
Score: 8.5
March
Score: 8.4
Ideal Conditions for Kohamajima Island
Water Temp
27.9°C / 82.2°F
June
Visibility
11.4m / 37.4ft
July
Wave Height
1.7m / 5.6ft
March
Wave Period
8.0s
January
Seasonal Insights for Kohamajima Island
Kohamajima Island shows typical northern hemisphere patterns with July being the warmest month (29.1°C) and January the coldest (15.5°C). The calmest conditions typically occur in March with average wave heights of 1.7m 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 0.7mm 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 16, 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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