Scuba Diving Thailand

When and where to go

    Thailand is an incredible country for scuba diving with its majestic coastline covering large parts of the Gulf of Thailand as well as a stunningly beautiful stretch of the Andaman Sea. Islands, bays, wrecks, caves, pinnacles and marine parks are available across the two seas and some of the dive sites are considered among the best in the world! This article covers the best dive areas in the country and takes a look at what's the best time of the year to visit each of them.

Monsoon season in Thailand

    Unlike many other countries of its size, Thailand experience different seasons depending on where you are in the country. This is due to its unique geography, with mountains to the north and a long coastline stretching south. For diving 2 separate monsoon seasons define the south of the country, one for the Gulf of Thailand and one for the Andaman Sea. Before we go on discussing the seasons keep in mind that each year is different and especially with recent years, the effects of climate change is becoming more apparent in the region.

    In the Gulf of Thailand the monsoon season usually starts in December and lasts through January. It can start earlier and it can end later, but rarely earlier then November and rarely later then February. During this season the winds blow in from the north-east, bringing clouds and rain from the seasonal hurricanes that usually strikes Vietnam, China and The Philippines.

The winds can bring relatively big waves, however due to the topography of the Gulf (it's very shallow) waves rarely reach higher then a few meters. It's extremely rare for any of the large Pacific storms to hit the Gulf as it's very well sheltered,

so mostly the bad weather that ends up hitting the area are just what's left of them after they have struck elsewhere.

While you can still dive at this time in locations like Koh Tao and Koh Chang (and it can even be great!), it's just more likely to have reduced visibility and larger swells on the boat.

    On the Andaman side the monsoon generally lasts longer. The best indicator for this is Similan national park, which closes down for 5 months of the year from May 15th to October 16th. Although you can't dive the famous national park at this time you can dive many of the dive sites closer to land further South. The area from Phuket to Koh Lipe with Krabi, Koh Phi Phi and Koh Lanta in between are situated in the south of the Andaman sea and diving is possible here all year around, however expect some of the better dive sites in the open ocean to be off limits during this time. Waves here can be larger then in the Gulf due to the depth of the oceans here but there are plenty of sheltered dive sites around the island for you to enjoy.

Best dive seasons in Thailand

    Highlighted above you can find a rough overview of the top 5 dive destinations in Thailand and the best times to visit them. Writing in gold indicated the best time of the year to visit each destination while writing in white indicates that diving is available however conditions may not be perfect. Please keep in mind that you can still have great diving in the off season and a surprise storm can cause reduced diving in peak season, weather and climate can always surprise you.

If you wish to learn more about the different destinations above and what kind of marine life you might encounter, check out the links below!

Similan National Park

Considered by many as the best diving in Thailand, Similan has a large variety of dive sites and is known for its stunning blue visibility. The park is open from the 16th of October until the 15th of May each year, with the rest of the year it stays closed due to the monsoon winds and waves of the season.


If you want to know more about the parks marine life, dive sites and our favorite months to visit check out the full article here.

Situated in the open ocean far from the mainland, Koh Tao is famous for its great diving. You can visit the island and dive here all year, however the best months is usually March – May and September through October/November. Koh Tao is also the best place in Thailand to spot whale sharks!

Check out the full article here to learn more.

Koh Tao

South Andaman

The area from Phuket to Koh Lipe with Krabi, Koh Phi Phi and Koh Lanta in between are situated in the south of the Andaman sea. They are located quite far from one another however they experience roughly the same weather patterns. The season here is similar to Similan as covered above with the best diving from November through April, however with the islands being closer to the mainland you can still dive in certain areas throughout the year.

More info about the islands and diving here.

Together with neighboring Koh Kood these islands are located close to the Cambodian border in the Gulf of Thailand. The Gulf has its monsoon season from November through January, however it can also catch some rainy weather during May – July. Best time to visit is February – April and September – October.


For more info read more here.

Koh Chang

Ko Losin

Perhaps Thailands best kept secret is Losin, located more then 320km south-east of Koh Samui in the Gulf of Thailand. It's widely considered a contender to the best diving in Thailand with some incredible visibility to boot. Due to its location however it's both hard to reach and the window to visit is narrow due to the weather in the region. The best months to visit is May & August, with July & September also possible.

Read more about Losin here.

Need help planning your dive trip to Thailand? Feel free to contact us for advice

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