The best islands in Thailand, and the coast you pick first
Thailand's two coasts run opposite monsoons, so your dates pick the coast before you pick the island. Nine islands by what they are for, and the routing rule.
Photo · Balazs Simon · Pexels
Almost every list of the best Thai islands ranks them against each other as though your dates were irrelevant.
They are not. Thailand's two coasts run opposite monsoons, which means the month you can travel picks the coast, and only then do you pick the island.
Get that order wrong and you can book the best island in the country in the one week it is unswimmable.
Thai baht. Convert any figure on this page into your own currency at today's published rate.
Open the currency converter →Step one: the coast
| Coast | Islands | In season | Wettest |
|---|---|---|---|
| Andaman, west | Phuket, Phi Phi, Lanta, Lipe | Mid-Nov to April | Roughly May to October |
| Gulf, east | Samui, Phangan, Tao | Roughly Jan to Sept | October to December |
The overlap is real: January to April, both coasts work, which is why that is Thailand's high season and priced accordingly.
The gap is also real: October is the one month neither coast is reliable. The Gulf is entering its wettest stretch and the Andaman has not dried out. September is close behind. If your dates are fixed in October, Bali is at the end of a good dry season and is the better answer.
Step two: the routing rule
Ferries within a coast take one to two hours and run frequently in season, so hopping along a chain is easy and cheap.
Crossing between the coasts burns most of a day, by road and boat or by a domestic flight through Bangkok or Surat Thani.
So: pick a chain and stay on it.
- Andaman chain: Phuket → Phi Phi → Lanta → Lipe
- Gulf chain: Samui → Phangan → Tao
Two islands in ten days is comfortable. Three is a travel schedule.
The Andaman islands, November to April
Koh Lanta, and this is our pick
Long, flat, quiet, and with proper roads, which sounds like faint praise until you have tried to move a family or a bag across an island without them.
The beaches shelve gently rather than dropping away, there is a national park at the southern tip, and the whole place has resisted becoming Phuket while sitting two hours from it.
Best for: families, longer stays, anyone who wants an island rather than a resort. The catch: it genuinely closes down in low season, more than most.
Koh Lipe
The furthest south, near the Malaysian border, and the clearest water in the country along with the Similans. Small enough to walk across, with three beaches and a walking street between them.
Best for: couples, snorkelling, people who want the postcard. The catch: getting there is a commitment, and it is small enough that four nights is plenty.
Koh Phi Phi
The scenery is genuinely extraordinary, which is why it is on every list and why it is as busy as it is. Limestone cliffs straight out of the sea, and Maya Bay, which has been through a closure and a managed reopening.
Best for: the landscape, and day trips from Phuket or Lanta. The catch: the main village is loud and crowded in season, and the island is better as a day trip or a two-night stop than a week.
Phuket
Not really an island holiday and it is on the list because it is the gateway. Phuket is a large, developed, well-connected place with an international airport, excellent food and some very good hotels, and the beaches are not the reason to come.
Best for: flying in, one night either end, and the old town, which is genuinely charming and which nobody visits. The catch: treating it as the beach destination rather than the door.
The Gulf islands, roughly January to September
Koh Tao, and this is the other pick
The best diving in Thailand and the cheapest place in the world to learn, with a concentration of dive schools that keeps standards up and prices down.
Best for: diving, snorkelling, and anyone who wants a small island with something to do. The catch: it is small and hilly, the roads are poor, and it is busy.
Koh Samui
The comfortable one. An airport, real hospitals, proper hotels, restaurants that are not aimed at backpackers, and enough infrastructure that you can arrive without a plan.
Best for: shorter trips, families who want facilities, anyone flying in rather than ferrying. The catch: it is developed, and the difference between the north coast and the south is substantial.
Koh Phangan
Famous for one party and unfairly defined by it. The Full Moon Party happens at Haad Rin and the rest of the island, particularly the north and east, is quiet, green and increasingly the wellness capital of the Gulf.
Best for: either the party or emphatically not the party, and the two are geographically separable. The catch: check the lunar calendar before you book, in whichever direction you care about.
The quick answer, by what you want
| If you want | Go to | Coast |
|---|---|---|
| Families, space, a real island | Koh Lanta | Andaman |
| Diving, and learning to | Koh Tao | Gulf |
| The clearest water | Koh Lipe, or the Similans | Andaman |
| Comfort and easy logistics | Koh Samui | Gulf |
| Scenery above all | Koh Phi Phi | Andaman |
| A party, or deliberately not one | Koh Phangan | Gulf |
| A gateway and a good old town | Phuket | Andaman |
A catalogue note, said plainly: the shelf above is Bangkok, because none of the islands on this page are destinations in our catalogue. Bangkok and Chiang Mai are the Thai cities we can show you rooms in. The timing and the routing on this page hold regardless, and we would rather tell you what we cannot do than show you a shelf for the wrong place.
What to skip
Booking the island before checking the coast. The whole argument of this page.
October and September, unless the island is incidental to the trip.
Three islands in ten days. Two, with the ferry time counted honestly.
A Similan trip between mid-May and mid-October. It does not exist.
Phuket's Patong beach as a destination. Phuket has a great deal going for it and that stretch is not it.
Assuming the Full Moon Party is the whole of Koh Phangan. The north of the island is a different holiday entirely, and most of the people there have no idea what date it is.
Visa-free · 60 days, on all five passports we check.
Short tourist stays only. Checked 21 Aug 2026; rules change without notice and the government page is the source of truth.
Check your own passport →Checked 21 Aug 2026.
Everything we check for Thailand →Before you book
Bali or Thailand is the higher-level version of this decision, and it turns on whether you want one place or a route. Where to travel in December and where to travel in January both put Thailand's coasts in the context of everywhere else in those months, and the best time to visit Bali is the comparison next door. The Bangkok city guide, the Chiang Mai city guide and the Thailand country guide have the practicalities. More in the best of hub and the when to go hub. Ready to look at rooms? Bangkok stays are here.
Seasons, park closures and routing checked September 2026 against the Tourism Authority of Thailand and the national parks service. The Similan closure dates are fixed annually and the monsoon windows are climatological averages rather than a forecast. Here is how we research and re-check guides.
