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Gulf of Thailand Options
Gulf of Thailand
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Koh Tao Day Trips
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Koh Samui Day Trips

Diving in Koh Samui

Gateway to the Gulf of Thailand

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...Highlights: whale sharks, turtles, schooling fish/big pelagics, non diving activities...
...Koh Samui's diving environment: beginner divers, very popular...

One of Thailand's best loved islands, Samui's charms are evident as soon as you arrive at its award-winning thatch-roofed airport.

When you stay on the island of Koh Samui you will not only enjoy the excellent beaches and wonderful nightlife, but you will also have access to the best scuba diving in this part of Thailand. The sites around Koh Tao can also be dived via daytrips from Samui. Show more

Dive Site Descriptions for Koh Samui

Sail Rock - This is a 30m tall granite pinnacle half way between Koh Phangan and Koh Samui and is thought of as the best dive site in the Gulf of Thailand. There are no other rocks nearby so it acts as a congregation point for all fishes in the surrounding area. It is a real highlight because whale sharks are commonly sighted here. Whether you are on the surface or below, you will be amazed at how long these sharks stay around seemingly enjoying the presence of divers.

On a sunny day when the light filters down into the aquamarine waters, the granite boulder looks spectacular. Schools of trevallies roam all over Sail Rock and energetically hunt the smaller fish that bunch together for protection from these darting raids. There are several more rocks a little deeper that can be seen from the main pinnacle and these are home to reef sharks. Show more

How to Dive Samui

These dive sites can be visited by high speed daytrip boats from Koh Samui Island. For more information on these great options, and all the other travel information you might need to visit Samui and the Gulf of Thailand, read our Koh Samui day trips section.

The high speed catamaran departs every morning, normally in small groups. You will normally return in time to return to your resort and relax for the late afternoon.

You can book these dive daytrips separately, or combine them with an accommodation package in one of our recommended Koh Samui resorts.

Koh Samui Diving Season

The dive sites in the Gulf of Thailand can be enjoyed throughout the year. However the peak season, which sees the optimum conditions, runs from March to September, with underwater visibility reaching up to 30-35m at its best. There may be a reduction in visibility during the October to November period when monsoon winds and swells can be present. However these are rarely sufficient to interfere with diving trips, except for maybe making boat journeys a little bumpier.

If you are planning a dive trip between November and February, Koh Samui is not the best bet since rain and wind, brought by the northeast monsoon, can visit the Gulf, causing waves and a drop in visibility to 10m. Visit the Weather and Climate websiteOpens in a new window for more details on the climate of Samui.

Water temperature ranges between 27°C and 30°C, with the coolest water in the months of October and December. The coolest time of the year however, is also the best chance to see sharks in the area as they prefer colder waters.

Whale sharks mainly visit the area in March and April, and again in September and October.

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Where is Samui Island and How Do I Get There?

Review our maps below of Koh Samui and its host country Thailand. Here, you will find information on how to get to Samui.

Map of Koh Samui (click to enlarge in a new window) Map of Thailand (click to enlarge in a new window)

Reef Summary

Depth: 5 - 40m
Visibility: 5 - 25m
Currents: Can be strong
Surface conditions: Calm to choppy
Water temperature: 27 - 30°C
Experience level: Beginner - advanced
Number of dive sites: ~6, but >20 including Koh Tao
Recommended length of stay: 5 days

Useful References

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