Phuket, Krabi, Koh Samui, Koh Phangan, Koh Tao, Koh Lanta… Which Thai island should you choose when you have one or two weeks? The answer depends on two things: how you like to travel and, above all, the month you go. Thailand has two seas with two different weather seasons. Here is a simple comparison, by traveller type, to help you decide which Thai island to choose.
Which Thai island to choose? Start with the calendar
Thailand’s islands sit on two coasts. To the west is the Andaman Sea: Phuket, Krabi and its islands (Phi Phi, Railay), Koh Lanta. To the east is the Gulf of Thailand: Koh Samui, Koh Phangan and Koh Tao. The monsoon does not reach them at the same time. That is the key to your choice.
- Andaman Sea: the best period runs roughly from November to April. From May to October, the southwest monsoon brings showers, wind and often rough seas. September and October are usually the wettest months.
- Gulf of Thailand: the weather is usually pleasant from January to August, sometimes into September, including the middle of summer when the Andaman side gets the rain. The heaviest rain falls from October to December.
In short: from December to March, the Andaman side is at its best. In July and August, the Gulf is often the safer bet. February usually works for both coasts. For details, read our guide to the best time to visit Thailand, month by month.
Good to know: the rainy season is not non-stop rain: there are often short showers with sunshine in between. But in low season some boat services are reduced or suspended, and a few small hotels close, especially on Koh Lanta. The Similan Islands National Park, a top diving spot on the Andaman side, closes every year from 16 May to 14 October. Check boat schedules before you book.
Andaman Sea: Phuket, Krabi and Koh Lanta
Phuket is the country’s largest island, linked to the mainland by a bridge. It has an international airport, a wide choice of hotels and very different beaches. Patong is lively and crowded; Kata and Karon are easier with children. It is the practical choice, not the wildest one.
Krabi is not an island but a coastal province. Most visitors stay in Ao Nang, where boats leave for Railay (reachable only by sea), the Phi Phi Islands and nearby islets. Limestone cliffs, kayaking, rock climbing: this is the place for scenery.
Koh Lanta is quieter: long beaches, a relaxed feel, few big resorts. A good option for families and for anyone who wants to slow down. But low season is noticeable here: wind, waves, and some beach restaurants closed from May to October.
Gulf of Thailand: Koh Samui, Koh Phangan and Koh Tao
Koh Samui is the best equipped of the three: an airport, good roads, private hospitals, hotels at every level. Chaweng is the liveliest beach; the north of the island, around Bophut or Choeng Mon, is calmer. Flights and accommodation are often more expensive than elsewhere.
Koh Phangan, its neighbour, has two faces. The southeast, around Haad Rin, is known for the Full Moon Party, a huge beach party on full-moon nights. The rest of the island is much quieter, with coves, forest and many yoga and wellness retreats.
Koh Tao is the small island of divers. There are many dive schools, and the first certification (Open Water, two to four days) usually costs between 10,000 and 12,500 THB, roughly €260–330 or $300–380, depending on the school and what is included (check before you go). Neither Koh Tao nor Koh Phangan has a working airport: you arrive by boat.
Which island for which traveller?
- Families: Koh Lanta for peace and quiet; Phuket (Kata, Karon) or northern Koh Samui for comfort and easy access. With young children, keep long boat transfers to a minimum.
- Couples: Krabi and Railay for the scenery, Koh Samui for beautiful hotels, northern Koh Phangan for privacy.
- Diving: Koh Tao to learn at a fair price; on the Andaman side, the Similan Islands (from Khao Lak or Phuket) for experienced divers, from mid-October to mid-May.
- Tight budget: Koh Tao, Koh Phangan and Koh Lanta have simple bungalows. Phuket and Koh Samui cost more, especially in high season.
- Peace and quiet: Koh Lanta, or the north and west of Koh Phangan.
- Nightlife and parties: Koh Phangan for the Full Moon Party in Haad Rin, Patong (Phuket) or Chaweng (Samui) for lively evenings. Keep the usual reflexes: stay in a group, watch your belongings, go home with reliable transport.
Getting to the islands from Bangkok
- Phuket and Krabi: about 1 h 20 to 1 h 35 of flying time, with many daily departures from both Bangkok airports, Suvarnabhumi and Don Mueang. By overnight bus, allow 12 to 13 hours to Phuket.
- Koh Lanta: fly to Krabi, then 2 to 3 hours by minivan, including a short car-ferry crossing. Shared minivans leave early, so pick a morning flight.
- Koh Samui: direct flights of about one hour, mostly with Bangkok Airways (Thai Airways also flies there). The airport is privately owned and tickets are often much more expensive than to Phuket.
- Koh Phangan, Koh Tao (and Samui on a budget): flight, night train or bus to Surat Thani, then a boat from Donsak pier. The night train from Krung Thep Aphiwat station takes about 9 to 10 hours. By catamaran, allow about 45 minutes to Samui, 1 h 30 to Phangan and just over 3 hours to Koh Tao. For Koh Tao, there is also the route via Chumphon (bus, then boat).
Schedules and fares change with the season: check before you go. To start your trip smoothly, see also how to get from the airport to central Bangkok.
Good to know: most island trips start or end with a few days in Bangkok. Mr Schaka’s free app Thaïlande en poche installs straight from the website and brings together the guide’s maps and addresses. Handy for a smooth stopover.
Summary: which island, when, for whom?
- Phuket (Andaman): November to April. Families, comfort, easy access.
- Krabi, Railay, Phi Phi (Andaman): November to April. Couples, scenery, climbing.
- Koh Lanta (Andaman): November to April. Families, quiet; marked low season.
- Koh Samui (Gulf): January to August. Couples, families, comfort; higher budget.
- Koh Phangan (Gulf): January to August. Parties in Haad Rin, quiet elsewhere, small budgets.
- Koh Tao (Gulf): January to August. Diving, tight budget.
With two weeks, Mr Schaka suggests combining two or three islands on the same coast: Phuket and Krabi, or Samui, Phangan and Tao, linked by boat. Mixing both coasts is possible, but depending on the month, one of them will be less favourable.
Frequently asked questions
Which island is best for a first trip to Thailand?
Phuket or Koh Samui: easy to reach by plane, plenty of hotels and services. Choose by month: Phuket from November to April, Samui from January to August.
Which island should I choose in July or August?
The Gulf: Koh Samui, Koh Phangan or Koh Tao. The Andaman Sea is then in full monsoon, often with rough seas.
And in November or December?
The Andaman Sea: Phuket, Krabi, Koh Lanta. The Gulf gets its heaviest rain at that time of year.
Can I reach the islands without flying?
Yes: night train or bus to Surat Thani or Chumphon, then a boat. It is cheaper, but expect a long day or a night of travel.
Want to dig deeper?
Mr Schaka’s guidebook, Koh Samui and the Islands – The Practical Guide, covers the essentials: transport, neighbourhoods, addresses, food, etiquette and safety, updated for 2026–2027.
