The right Thai island depends on three things: who you are traveling with, what you want to do, and when you are going. As a quick answer: Koh Lanta or Koh Samui for families, Koh Kood or Koh Lipe for couples who want quiet, Koh Tao for learning to dive, Koh Phangan or Phi Phi for a social scene, and Koh Samet for a short break from Bangkok. Then check that your island is in season.
Thailand has hundreds of islands, but visitors mostly choose between about a dozen, in three groups. The Andaman islands (Phuket, Phi Phi, Koh Lanta, the Trang islands, Koh Lipe) lie off the west coast. The Gulf islands (Koh Samui, Koh Phangan, Koh Tao) lie off the east coast of the south. The eastern islands (Koh Samet, Koh Chang, Koh Mak, Koh Kood) lie closest to Bangkok. Our Thai islands overview lists every island guide on the site.
This page matches islands to travelers. It does not rank them, because the best island for a diver is the wrong one for a family with a toddler. Use the matrix first, then read the section for your type of trip.
The decision matrix
| You are… | First choice | Also consider | Best months |
|---|---|---|---|
| A family with children | Koh Lanta | Koh Samui, Koh Chang | Lanta Nov–Apr; Samui Jan–Sep; Chang Nov–Apr |
| A couple wanting quiet | Koh Kood | Koh Lipe, Koh Mak, the Trang islands | Nov–Apr |
| Learning to dive | Koh Tao | Phi Phi, Koh Lanta | Tao Jan–Sep; Andaman Nov–Apr |
| An experienced diver | Similan Islands (liveaboard or day trip) | Koh Tao, Koh Lipe | Similan 15 Oct–15 May only |
| A backpacker or after nightlife | Koh Phangan | Phi Phi, Koh Tao | Phangan Jan–Sep; Phi Phi Nov–Apr |
| Staying a month or more | Koh Lanta or Koh Phangan | Koh Samui, Koh Chang | Depends on the coast (see below) |
| Short of time, starting in Bangkok | Koh Samet | Koh Samui (by air) | Samet Nov–Apr is driest |
| Traveling in June to September | Koh Samui, Koh Phangan, Koh Tao | Koh Samet | Gulf is relatively dry Jun–Aug |
| Traveling in November | The Andaman islands | Koh Chang, Koh Samet | Gulf is at its wettest |
Start with the season
The season rules out more islands than anything else. The Thai Meteorological Department's 1991–2020 averages show the Andaman side (Phuket) dry from January to March and wettest in September and October, while Koh Samui in the Gulf gets half its year's rain from October to December, with November the wettest month. The eastern islands near Trat follow the Andaman pattern, with very heavy rain from May to September.
In practice: from November to April almost everything works, apart from the Gulf in November and December. From June to September, the Gulf islands are the best bet. Our guide to the best time for the Thai islands goes month by month.
Families with children
Families need short transfers, calm water, space and medical care within reach. Koh Lanta fits well: it is reached by road from Krabi or by boat from Phuket and Phi Phi, has long sandy beaches on its west coast and a relaxed pace. It is also on the US CDC's list of Krabi islands with no malaria transmission. Koh Samui has its own airport and the widest choice of hotels in the Gulf, and it is the Gulf choice for school holidays in July and August.
Koh Chang, Thailand's third-largest island, is the family choice in the east: reachable by road and car ferry from Bangkok, with many hotels. Avoid the islands that need several boat changes, or where your bags have to be passed from a speedboat to a longtail at sea, if you are traveling with small children.
Couples who want quiet
For quiet, go further out. Koh Kood near the Cambodian border has clear water, waterfalls and very little development, but take cash and go between November and April. Koh Lipe in the far south has reefs close to the beach and is easy to combine with Langkawi in Malaysia, which suits visitors from Malaysia and Singapore. Our guide to the smaller Andaman islands covers Koh Yao Noi and the Trang islands, which are quieter still.
Couples who want comfort as well as calm often prefer the quieter north coast of Samui or a resort on one of the smaller bays of Koh Chang. Remote does not have to mean basic, but it usually means fewer restaurants and more planning.
Divers and snorkelers
Koh Tao is one of the world's busiest places to learn to dive, with many dive schools and the Gulf's long dry season from January to September. Our guide to learning to dive on Koh Tao explains how to choose a school.
Experienced divers usually head to the Andaman side. The Similan Islands are open only from 15 October to 15 May each year; foreign adults pay a 500-baht park fee, and all visitors must buy tickets through the national park's e-ticket system (October 2026). Phi Phi and the islands off Koh Lanta also have well-known dive sites. Snorkelers can do well almost anywhere in season; Koh Lipe and Koh Kood have reefs close to shore.
Backpackers and nightlife
Koh Phangan is the best-known party island, with the Full Moon Party on Haad Rin's Sunrise Beach. The rest of the island is quiet, with yoga retreats and calm bays, so you can party for a night and rest for a week. Our guide to the Full Moon Party covers dates and safety; the UK FCDO notes that sexual assaults are most common during full moon parties and similar events.
Phi Phi Don is the Andaman equivalent: compact, car-free and busy at night, with the boat trip to Maya Bay on the doorstep. It is also expensive for what you get, and fresh water is short in the dry season. Koh Tao combines diving with a social scene around its main beach.
Long stays and remote work
For a month or more, pick an island with roads, supermarkets, reliable internet and healthcare, and match it to the season. Koh Lanta works from November to April; Koh Phangan and Koh Samui work for most of the year outside October to December. Koh Chang is the eastern option. Remember the paperwork: most visitors from visa-exempt countries get 30 days on arrival as of October 2026, so read our guide to the visa exemption before you plan a longer stay.
A short break from Bangkok
With two or three nights, do not spend one of them in transit. Koh Samet is the closest real beach island: a bus to Ban Phe and a short ferry, about half a day in total. It is part of a national park (200 baht for foreign adults) and busiest at weekends. With an extra night and a flight, Koh Samui is the other choice. Our overview of the eastern islands compares Samet with Koh Chang, Koh Mak and Koh Kood.
Count the transfers, not the distance. An island one flight and one taxi away is closer in practice than one with a bus, a ferry and a longtail. For short trips, choose islands with a single, frequent crossing.
More than one island?
Combining islands is easy within one group and hard between groups. Stay on one coast and follow our island-hopping guide, which links to the Andaman and Gulf routes and explains tickets, luggage and safety.
Frequently asked questions
Which Thai island is best for first-timers?
Koh Samui in the Gulf or Koh Lanta on the Andaman side. Both have easy transfers, a wide choice of hotels and good services, without being as crowded as Phuket's busiest beaches. Choose by season: Lanta from November to April, Samui from January to September.
Which Thai island is best in July and August?
The Gulf islands. At the Koh Samui weather station, June to August average about 100–135 mm of rain a month, compared with 240–310 mm in Phuket town. Koh Samui, Koh Phangan and Koh Tao are the usual choices for the European and Asian summer holidays.
Which island is closest to Bangkok?
Koh Samet, off the Rayong coast. Allow about half a day: a bus from Ekkamai to Ban Phe, then a ferry of around 40 minutes. Koh Chang is further east and takes most of a day by road and car ferry.
Which Thai island is quietest?
Among the islands covered on this site, Koh Kood, Koh Mak and the Trang islands are the quietest, with few roads and little nightlife. They are best from November to April, when the boats run regularly and the sea is calm.
Is Koh Phangan only for parties?
No. The Full Moon Party takes place on one beach at Haad Rin, at the south-east tip. The north and west coasts are quiet, with small bays, yoga retreats and family resorts, and many visitors never go to a party.
Sources
- Thai Meteorological Department – Climatological data 1991–2020 (checked October 2026)
- Pollution Control Department, Region 13 – Thailand's largest islands (DMCR data, in Thai) (checked October 2026)
- US CDC – Health information for travelers to Thailand (malaria) (checked October 2026)
- Department of National Parks – Similan e-ticket rules (in Thai) (checked October 2026)
- The Nation – Similan and Surin closed 15 May to 15 October 2026 (checked October 2026)
- UK FCDO – Thailand: safety and security (checked October 2026)
- Tourism Authority of Thailand – Ko Samet (checked October 2026)
- Ministry of Foreign Affairs of Thailand – 30-day visa exemption list (15 September 2026) (checked October 2026)