Thailand · Andaman Sea and Gulf of Thailand
Thai islands: which one to choose
Limestone cliffs in the Andaman Sea, diving islands in the Gulf, beaches for relaxing and others for partying: Thailand has islands on two coasts with different seasons. Here are the most visited and when to go to each.
Updated 20 October 2026 · How we make our guides
Andaman Sea (west coast)
The best time is November to April; from May to October the monsoon rains arrive.
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ThailandPhuket
The largest island, with beaches for every taste, the Sino-Portuguese old town and trips to Phang Nga Bay.
What to see in Phuket -
ThailandKrabi
The cliffs of Railay, a rock-climbing paradise, Ao Nang and trips to the nearby islands.
What to see in Krabi -
ThailandPhi Phi Islands
Postcard islands with turquoise water; Maya Bay is visited with a daily cap and no swimming, to protect the reef.
What to see in Phi Phi Islands -
ThailandKoh Lanta
Quieter, with long beaches and a relaxed atmosphere, very good for families.
What to see in Koh Lanta
Gulf of Thailand (east coast)
A different season: the best runs from January to August, and the heavy rains come from October to December.
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ThailandKoh Samui
Palm-fringed beaches, the Big Buddha and its own airport: the most convenient island in the Gulf.
What to see in Koh Samui -
ThailandKoh Phangan
Famous for the Full Moon Party at Haad Rin, but with a quiet north of coves and jungle.
What to see in Koh Phangan -
ThailandKoh Tao
One of the most popular places in the world to get a diving certificate, with good snorkelling from the beach.
What to see in Koh Tao
Frequently asked questions
Which Thai islands should you choose?
For a first visit between November and April, Krabi, Phi Phi and Ko Lanta in the Andaman Sea; in summer, Ko Samui, Ko Pha Ngan and Ko Tao in the Gulf of Thailand.
When is the best time to visit the Thai islands?
It depends on the coast: the Andaman Sea (Phuket, Krabi, Phi Phi, Lanta) from November to April; the Gulf (Samui, Pha Ngan, Tao) from January to August.
Which island is best for diving?
Ko Tao, to learn and get certified; and in the Andaman Sea, trips from Phuket and Khao Lak to the Similan Islands in season.
And for children?
Ko Lanta and Ko Samui, for their calm beaches and relaxed atmosphere.
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Reviewed 20 October 2026. Dates and seasonal warnings: the same data the Bagintravel app uses. Sources and method.
Cover photo: kallerna (CC BY-SA 3.0), Wikimedia Commons.