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Koh Racha Yai, Phuket in Thailand

Ratchayai Island, situated approximately 20 km south of Phuket in Thailand, is a fantastic dive site that offers year-round diving opportunities. However, the optimal conditions can be experienced during the rainy season, which spans from May to October. Among the surrounding islands, the eastern dive site at Ratchayai Island boasts remarkably clear waters, making it particularly enticing for divers.

Divers exploring Ratchayai Island's underwater realm will be mesmerized by the vibrant coral and intricate roots that adorn the sandy seabed. This captivating landscape is home to a diverse array of marine life, including damselfish, butterfly fish, grouper, and numerous other fascinating creatures and fish species.

The eastern side of the island hosts multiple dive sites, each offering their unique charm. Divers can also explore wrecks and artificial fish reefs, which are immensely popular. On the other hand, the west side of Ratchayai Island is an excellent choice for diving enthusiasts during the high dry season. The island's largest bays, Bungalow Bay and Siam Bay, are particularly attractive to divers who seek thrilling underwater adventures.

Ratchayai Island's exceptional diving conditions boast a visibility of up to 14 meters and a maximum depth of 17 meters. This makes it an ideal destination for both beginner and advanced divers. Situated in close proximity to Phuket Province in Thailand, reaching Ratchayai Island may require navigating challenging roads. However, the breathtaking views make the journey all the more worthwhile.

Experience the wonders of Ratchayai Island's underwater paradise, and embark on unforgettable diving adventures in Thailand.

Diving Conditions Score for Koh Racha Yai, Phuket in Thailand

7.5
Good

Good diving conditions!
The score is based on a calculation of the current weather and sea conditions.

Dive Site Overview for Koh Racha Yai, Phuket in Thailand

Depth

17m

Visibility

14m

Experience Level

beginner
advanced

Weather Conditions for Koh Racha Yai, Phuket in Thailand

Wave Height

0.66m

Wind Speed

15.4 m/s

Water Temp

30.7°C

Visibility

17.14km

Cloud Cover

98%

Wave Period

6.45s

Air Temperature

27.6°C

Precipitation

1.5 mm

Detailed 7-Day Diving Forecast for Koh Racha Yai
Alpha

Dive Score Chart for Koh Racha Yai

Best time to dive: 17:00 with score 8.322599516908213/10. Water conditions: Waves 0.62m, Wind 12.8 m/s.Best night dive time: 19:00 with score 7.87155744680851/10.

Chart showing hourly dive conditions including wave height, wind speed, water temperature, and visibility throughout the day.

Sunrise at Koh Racha Yai: 06:00
Sunset at Koh Racha Yai: 18:00

Optimal diving conditions at Koh Racha Yai 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
17:00

Score: 8.3/10
Waves: 0.62m (6.9s), Wind: 12.8 m/s

🌞
Safest Overall
6:00

Score: 8.3/10
Waves: 0.6m (6.9s), Wind: 18.6 m/s

🌙
Best Night
19:00

Score: 7.9/10
Waves: 0.6m, Wind: 12.9 m/s

Seasonal Analysis for Koh Racha Yai, Phuket in Thailand
Alpha

Historical patterns and best seasons for diving at Koh Racha Yai, Phuket in Thailand

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 Koh Racha Yai, Phuket in Thailand

Winter

Avg. Score: 10.0/10

Winter offers the best overall diving conditions with calmer seas and better visibility, despite cooler temperatures.

Best Months for Koh Racha Yai, Phuket in Thailand

January
Score: 10.0
February
Score: 10.0
March
Score: 10.0

Ideal Conditions for Koh Racha Yai, Phuket in Thailand

Water Temp

Thermometer Emoji

27.0°C / 80.6°F

July

Visibility

Telescope Emoji

10.4m / 34.1ft

January

Wave Height

Wave Emoji

2.0m / 6.6ft

November

Wave Period

Wave Emoji

8.0s

January

Seasonal Insights for Koh Racha Yai, Phuket in Thailand

Koh Racha Yai, Phuket in Thailand shows typical northern hemisphere patterns with May being the warmest month (27.4°C) and December the coldest (22.0°C). The calmest conditions typically occur in November with average wave heights of 2.0m and wave periods of 8.0s. The most comfortable wave conditions are in November 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). January is usually the driest month with 0.1mm of precipitation. For beginners, the best time to visit would be during November to January, 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.

Scoring Legend:
9-10 (Excellent)
7-8 (Good)
5-6 (Average)
3-4 (Poor)
1-2 (Dangerous)

Last updated: 1 min. ago - Jun 21, 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.

The closest dive destination to Koh Racha Yai is Phuket

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