Before you compare the best islands in Thailand, know the one fact that decides everything: the two coasts run on opposite seasons. The Andaman side in the west (Phuket, Phi Phi, Lanta, Lipe) gets its heavy weather roughly May to October, worst in September. The Gulf side (Samui, Phangan, Tao) stays dry through most of that, then takes its own beating from October to December, worst in November. So the month you travel picks your coast, and your coast picks your island.
This guide compares islands as places, not beaches. For sand by name, see our beach by beach guide to Thailand's best beaches. Here it is what each island is like, who it suits, how you get there, and one honest warning each.
Phuket
Phuket is the only Thai island with a full international airport, which makes it the easiest to reach and the natural first stop. It is big and developed, more coastal province than island, with a quiet bay and a loud strip within the same half hour drive.
Beyond the sand there is Old Town with its Sino Portuguese shophouses and boat access to most of the Andaman. Give it three or four nights. Warning: the west coast surf from May to October is genuinely dangerous, and people drown there every year when red flags go up.
Koh Phi Phi
Two islands, one name. You stay on Phi Phi Don, which has the hotels, the pier and the bars. Phi Phi Leh is uninhabited national park and holds Maya Bay. Ferries from Phuket or Krabi take about two hours.
Maya Bay reopened under strict rules: no swimming, boats enter through Loh Samah at the back instead of landing on the beach, and the bay closes every year from 1 August to 30 September. Two nights is plenty. Warning: Tonsai village at night is loud in a way you cannot escape, so sleep elsewhere on the island.
Koh Lanta
Lanta is for people who want the Andaman coast without the noise. It is long and flat with a road down the spine, so a scooter and a slow drift between bays is the whole point. The south end has a national park headland, and Lanta Old Town is a row of stilt houses over the water.
From Krabi it is about two hours by minivan, a short car ferry, then the bridge to Lanta Yai. Divers come for Hin Daeng and Hin Muang. Warning: those sites and nearby Koh Rok close from 1 July to 30 September.
Koh Lipe
Lipe is the far south of the Andaman islands Thailand keeps for people willing to travel. It is tiny, walkable in an hour, ringed by clear shallow water and inside Tarutao National Marine Park. Snorkeling off the sand beats almost anywhere else in the country.
Getting there is the work: fly to Hat Yai or Trang, road transfer around two hours to Pak Bara pier, then a speedboat of roughly ninety minutes. Warning: boats thin out badly in low season, so treat Lipe as a high season island.
Koh Yao Noi
Koh Yao Noi sits in Phang Nga Bay between Phuket and Krabi and stays quiet on purpose. It is a Muslim fishing and farming community of a few thousand people, with rice fields, rubber trees and no nightlife.
Speedboats run from Bang Rong pier on Phuket's east coast in about thirty minutes, and boats also come from Krabi. Kayaking among the limestone stacks is the reason to come. Warning: the tide goes out a long way, so plan swimming around it or book somewhere with a pool.
Koh Samui
Samui is the Gulf's answer to Phuket and Thailand's second largest island. Its own airport takes flights from Bangkok in around ninety minutes, which is why it draws couples and families who do not want a long boat ride. A ring road connects everything, so a quiet north coast bay still puts you near good food.
Inland there are waterfalls and a big Buddha, and day boats run to Ang Thong Marine Park, which closes from 1 November to 15 December. Couples often pair Samui with the capital, which is what our Bangkok and Koh Samui Honeymoon Tour is built around.
Koh Phangan
Phangan has a reputation problem. The Full Moon Party happens on one beach, Haad Rin, once a month. The rest of the island is nothing like it: jungle roads, waterfalls, yoga studios around Sri Thanu, and the two calm bays at Thong Nai Pan on the northeast side.
It is ferry only, about thirty minutes from Samui or four to seven hours from the mainland at Surat Thani. Warning: if you are not there for the party, check the lunar calendar first, because rooms and boats around full moon are hard to get.
Koh Tao
Koh Tao certifies a huge share of the world's new scuba divers, and the reason is practical. Dive sites sit close to shore, the bays are shallow and sheltered, the water stays warm year round, and dozens of schools compete here, so courses run every day.
You arrive by catamaran, roughly an hour and a half from Samui or two hours from Chumphon. Warning: Sairee is the main beach and also the main boat channel, so swim inside the marked buoys. Traffic there is constant and swimmers drift too close to it.
Koh Chang
Koh Chang is Thailand's third largest island, not the second, despite what many sites still say. Samui is bigger. What Chang has is mountains: the interior is steep rainforest with waterfalls like Klong Plu, and the beaches string along one west coast road below it.
From Bangkok it is five to six hours by bus to Laem Ngop, or a short flight to Trat plus a transfer, then a car ferry of about thirty minutes. Warning: that coast road is steep and badly cambered in places, and scooter accidents are common.
Koh Kood
Koh Kood is the quietest island here that still has real resorts. It sits further from Bangkok than Koh Chang and is reached only by boat from Laem Sok pier near Trat, about an hour by catamaran. That distance is why it stays empty.
It is mostly jungle, with a few waterfalls, a stilt fishing village at Ao Salad, and beaches often empty on a weekday. Warning: boats shrink through the monsoon months and some operators stop entirely, so confirm your return crossing early.
Similan Islands
The Similans are a day trip or a liveaboard, never a base. Overnight stays on the islands have been banned since 2018, so no tents and no bungalows. The park opens only from mid October to mid May and closes for the rest of the year.
Boats leave Thap Lamu pier near Khao Lak, about an hour to ninety minutes by speedboat. Book from Khao Lak rather than Phuket unless you enjoy a very early van ride. Warning: daily visitor caps apply, so booking on the day rarely works.
Koh Samet
Samet is for people with two or three days, not two weeks. It is close enough to Bangkok to reach in about four hours door to door, by road to Ban Phe pier then a ferry of forty minutes or a speedboat in ten. The whole island sits inside Khao Laem Ya national park, and it works year round.
Warning: this is the Bangkok weekend island, so Friday and Saturday nights are packed and the beach bars run late. Midweek it is a different place.
Comparing the Thai islands at a glance
| Island | Coast | Getting there | Best for | When to go |
|---|---|---|---|---|
| Phuket | Andaman | Own international airport | First timers, short trips | Nov to Apr |
| Koh Phi Phi | Andaman | Ferry from Phuket or Krabi | Scenery, young travelers | Nov to Apr |
| Koh Lanta | Andaman | Road and car ferry from Krabi | Families, slow trips, divers | Nov to Apr |
| Koh Lipe | Andaman | Hat Yai or Trang, then Pak Bara boat | Snorkeling, clear water | Nov to Apr |
| Koh Yao Noi | Andaman | Speedboat from Phuket or Krabi | Quiet, kayaking, couples | Nov to Apr |
| Koh Samui | Gulf | Own airport, or ferry from Donsak | Couples, families, comfort | Jan to Sep |
| Koh Phangan | Gulf | Ferry from Samui or Surat Thani | Wellness, nightlife, backpackers | Jan to Sep |
| Koh Tao | Gulf | Catamaran from Samui or Chumphon | Learning to dive | Jan to Sep |
| Koh Chang | East | Bus or Trat flight, then car ferry | Jungle, waterfalls, value | Nov to Apr |
| Koh Kood | East | Boat from Laem Sok near Trat | Quiet, honeymoons | Nov to Apr |
| Similan Islands | Andaman | Day boat from Khao Lak | Diving, snorkeling | Mid Oct to mid May |
| Koh Samet | East | Road to Ban Phe, then short ferry | Short breaks near Bangkok | Year round |
Which island in Thailand suits you
- First timer: Phuket or Samui. Both have airports and you can change your plans on the day.
- Couples: Koh Yao Noi or Koh Kood for real quiet, Samui if you want restaurants and spas too.
- Families: Koh Lanta and Koh Samui, for flat roads, calm bays and short transfers.
- Divers: Koh Tao to learn, the Similans and Hin Daeng after that.
- Backpackers: Koh Phangan, Koh Tao and Koh Chang, in that order.
- People who want silence: Koh Kood, Koh Yao Noi, or the far north of Koh Lanta.
- Only a few days: Koh Samet from Bangkok, or Phuket if you fly in anyway.
How to combine two islands without losing days
The rule for island hopping Thailand style is simple: pair islands on the same coast and never cross the country mid trip. Phuket with Phi Phi or Lanta works because ferries connect directly, and Samui with Phangan or Tao works the same way. Phuket with Samui burns a flight and half a day.
Two islands in ten days is comfortable, three is rushing. Never book a same day onward flight after a monsoon ferry, because cancellations are routine when the sea turns rough. Park closure dates shift each year, so confirm current rules with the Thai Department of National Parks before you commit.
To see how the islands fit with the mainland, read where to go in Thailand, and for wider questions read is Thailand safe. When you are ready to build a trip, browse our Thailand tour packages.
Frequently asked questions about Thailand's islands
Which is the best island in Thailand for a first visit?
Phuket for the Andaman coast and Koh Samui for the Gulf. Both have their own airports, so you skip long ferry rides, and both run day trips to quieter islands nearby.
When should I choose the Gulf islands over the Andaman islands?
Choose the Gulf islands Thailand offers, meaning Samui, Phangan and Tao, roughly between May and October when the Andaman coast is wettest. Flip to the Andaman side from November to April, when the Gulf gets its own monsoon.
Can you still visit Maya Bay on Koh Phi Phi?
Yes, but swimming is banned and boats enter from the back at Loh Samah rather than landing on the sand. Maya Bay also closes every year from 1 August to 30 September for reef recovery.
Can you stay overnight on the Similan Islands?
No. Overnight stays on the Similan Islands have been banned since 2018, so there are no tents or bungalows. Visit on a day boat from Khao Lak or sleep on a liveaboard, and only between mid October and mid May.
Is Koh Phangan only about the Full Moon Party?
No. The party is on one beach, Haad Rin, once a month. The rest of Koh Phangan is jungle, waterfalls, yoga retreats around Sri Thanu and the quiet twin bays at Thong Nai Pan, which feel like another island.
How many islands should I visit in one trip?
Two islands in ten days is comfortable, three is usually rushing. Pick islands on the same coast so ferries connect directly, and leave a buffer day before any flight home in case a crossing gets canceled.
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