Thailand is home to an astonishing array of islands offering all manner of diving, swimming and sunbathing opportunities all year round. The hardest part for any visitor is singling out Thailand's best islands among the hundreds. Here are 20 of our favourites (listed in no particular order), taken from the Rough Guide to Thailand’s Beaches & Islands. And remember, if you're after a relaxing trip, our Tailor-Made Trips service can help. Get in touch and we'll connect you with a local expert to start planning your dream holiday.
Thailand's best islands: get your bearings
Thailand has islands on all three sides. In the Andaman Sea on the west coast you'll find Ko Phi Phi and Ko Lanta. On the east and west sides of the Gulf of Thailand, you'll find places like Ko Samui, Ko Pha Ngan and Ko Tao. Getting around in high season is easy, with regular ferry services and internal flights. In low season ferry services may stop, but you'll nearly always find pricier speedboat transfers available.
Gulf of Thailand
1. For beaches: Ko Chang
Edged with white-sand beaches and backed by jungle-clad hills, Ko Chang is developing fast but still feels green. It’s Thailand’s second-largest island, after Phuket. Unlike its bigger sister, it has tourist facilities in its densely forested interior, just a few rivers, waterfalls and hiking trails. The island is popular with package tourists, but it’s still possible to find accommodation to suit most budgets. Although the beaches may be busy, there are plenty of places to swim or snooze under a palm tree.
Find places to stay on Ko Chang
A white-sand Ko Chang beach © Vlad61/Shutterstock
2. For relaxation: Ko Si Chang
The unhurried pace and absence of consumer pressures head to tiny, rocky Ko Si Chang. Unlike most other east coast destinations, there's no real beach scene. However, the water can be beautifully clear and there are opportunities to dive and snorkel. There’s little to do here but explore the craggy coastline by kayak or ramble up and down the steep contours on foot or by motorbike.
3. For parties: Ko Pha Ngan
For drinking and dancing, Ko Pha Ngan gets a mention thanks to its famous party beach, Hat Rin. It’s now established as the major party venue in Southeast Asia. In peak seasons – August, December and January – thousands flock here for the infamous Full Moon parties. The atmosphere created by thousands of folk mashing it up on the beautiful, moonlit beach, is a real buzz. Unfortunately, drug-related horror stories are common currency here, and many of them are true, so be careful.
Ko Pha Ngan, one of Thailand's party islands © Diego Fiore/Shutterstock
4. For a short hop: Ko Samet
Blessed with the softest, squeakiest sand within weekending distance of Bangkok, the tiny island of Ko Samet, which measures just six kilometres from top to toe, is a favourite escape for Thais, expats and tourists. Its 14 small but dazzlingly white beaches are breathtakingly beautiful, lapped by pale blue water and in places still shaded by coconut palms and the occasional cajeput (samet) tree that gave the island its name. The beaches are also, however, rather overcrowded and developed to full capacity, so don’t come here expecting a secluded break.
5. For the slow life: Ko Mak
Small, slow-paced, peaceful Ko Mak makes an idyllically low-key alternative to Ko Chang. Home to little more than 400 people, many of them descended from the islands’ five main clans, Ko Mak measures just 16 square kilometres and is dominated by coconut and rubber plantations. The island is shaped like a star and has fine white-sand beaches where most of the tourist accommodation is concentrated.
Life goes slowly onKo Mak, Thailand © DeltaOFF/Shutterstock
6. For mangroves: Ko Kood
The fourth-largest island in Thailand, forested Ko Kood (sometimes spelled Ko Kut or Ko Kud) is still a wild and largely uncommercialised place. Though it’s known for its sparkling white sand and exceptionally clear turquoise water, particularly along the west coast, Ko Kood is as much a nature lover’s destination as a beach bum’s. Swathes of shoreline are fringed by scrub and mangrove rather than broad sandy beaches, and those parts of the island not still covered in virgin tropical rainforest are filled with palm groves and rubber plantations. Ko Kood is a surprisingly pleasant place to explore on foot (or kayak), especially as the cool season brings refreshing breezes most days.
7. For learning to dive: Ko Tao
Ko Tao (Turtle Island) is so named because its outline resembles a turtle nosediving towards Ko Pha Ngan, 40km to the south. The rugged shell of the turtle, to the east, is crenellated with secluded coves where one or two bungalows hide among the rocks. On the western side, the turtle’s underbelly is a long curve of classic beach, Hat Sai Ree, and the 21 squared kilometres of granite in between is topped by dense forest on the higher slopes and dotted with huge boulders that look as if they await some Easter Island sculptor. There are rough trails inland that are great for exploring but Ko Tao is most famous for its great scuba diving. For those looking to learn how to dive on holiday Ko Tao has to rank as one of Thailand's best islands.
Anemone and Clownfish seen at Ko Tao, Thailand © Vlad61/Shutterstock
8. For going car-free: Ko Chang
No, we’re not repeating ourselves, this is a different Ko Chang, not to be confused with its much larger namesake off the east coast of Thailand. It’s a forested little island about 5km offshore, whose car-free, ultra laid-back, roll-your-own vibe more than compensates for the less-than-perfect beaches. The pace of life here is very slow and for the relatively small number of tourists who make it to the island the emphasis is strongly on kicking back and chilling out. Bring your own hammock and you’ll fit right in.
9. For a chilled expat vibe: Ko Phayam
The diminutive kangaroo-shaped island of Ko Phayam offers fine white-sand beaches and coral reefs and is home to around 500 people, most of whom either make their living from prawn, squid or crab fishing, or from growing cashew nuts, sator beans, coconut palms and rubber trees. Because of its roads, Ko Phayam has a slightly more developed feel than neighbouring Ko Chang, underlined by a low-key beach-bar scene – all hand-painted signs and driftwood sculptures – and the presences of a significant number of foreigners who choose to spend six or more months here every year.
Ko Phayam has a chilled vibe © ksl/Shutterstock
10. For untouched beauty: Ko Ra
Hilly, forested Ko Ra (measuring about 10km north to south and 3km across) sits just off Khuraburi pier’s mangrove-lined estuary and is covered with intact rainforest full of towering trees, hornbills and wild, empty beaches. The island is home to some two-dozen Moken and Mai Tai people and offers great hiking opportunities.
11. For snorkelling: Surin Islands
Spectacularly varied and unusually shallow reefs, a palette of awesomely clear turquoise waters and dazzling white sands, and dense forests of lofty dipterocarps combine to make the islands of Mu Ko Surin National Park one of the must-visit destinations in south Thailand. It’s very much an outdoors experience, with most of the bulk of accommodation in national park tents, no commerce on the island at all, and twice-daily snorkelling the main activity.
Relaxing on one of the Surin islands, Thailand © DC_Aperture/Shutterstock
12. For experienced divers: Similan Islands
Rated as one of the world’s best spots for both above-water and underwater beauty, the eleven islands at the heart of the Mu Ko Similan National Park are among the most exciting diving destinations in Thailand. Massive granite boulders set magnificently against the turquoise waters give the islands their distinctive character, but it’s the thirty-metre visibility that draws the divers. The underwater scenery is nothing short of overwhelming here: the reefs teem with coral fish, and you’ll see turtles, manta rays, moray eels, sea snakes, red grouper and possibly white tip sharks, barracuda, giant lobster and enormous tuna.
13. For the beach bum life: Ko Jum
This is the sort of laidback spot people come to for a couple of days, then can’t bring themselves to leave. Though there’s plenty of accommodation on the island, there’s nothing more than a handful of beach bars for evening entertainment, and little to do during the day except try out the half-dozen west coast beaches and read your book under a tree. Nights are low key: it’s paraffin lamps and starlight after 11pm at places off the main grid, and many places don’t even provide fans as ocean breezes are sufficiently cooling.
A jungle lodge on Ko Jum © tropical-travel/Shutterstock
14. For a peaceful escape: Ko Yao Noi
Located in an idyllic spot on the edge of Phang Nga bay, almost equidistant from Phuket, Phang Nga and Krabi, the island of Ko Yao Noi enjoys magnificent maritime views from almost every angle and makes a refreshingly tranquil getaway. Measuring about 12km at its longest point, it’s home to some four thousand islanders, most of whom earn their living from rubber and coconut plantations, fishing and shrimp-farming. While the beaches don’t have that same wow factor as many of the other islands in Thailand, tourism here is low-key so it’s a peaceful escape.
15. For families and couples: Ko Lanta
Although Ko Lanta Yai can’t compete with neighbouring Ko Phi Phi's stupendous scenery, the thickly forested 25-kilometre-long island has the longest beaches in the Krabi area – and plenty of them. There’s good snorkelling and diving nearby, plus caves to explore, trekking and kayaking. Many people base themselves here for their entire holiday fortnight. The island is especially popular with families, in part because of the local laws that have so far prevented jet-skis, beachfront parasols and girlie bars from turning it into another Phuket.
Sunset on the beach in Ko Lanta © Adel Newman/Shutterstock
16. For honeymooners: Ko Ngai
The most developed of the Trang islands, Ko Ngai (also known as Ko Hai) is still decidedly low-key. The island’s action, such as it is, centres on the east coast, where half a dozen resorts enjoy a dreamy panorama of jagged limestone outcrops, whose crags glow pink and blue against the setting sun, stretching across the sea to the mainland behind. The gently sloping, fine white sand beach here runs unbroken for 2km and there’s some good snorkelling in the shallow, clear water off the island’s southeastern tip.
17. For clear blue sea: Ko Kradan
Ko Kradan is the remotest of the inhabited islands off Trang, and one of the most beautiful, with crystal clear waters. On this slender triangle of thick jungle, the main beach is a long strand of steeply sloping, powdery sand on the east coast with fine views of Ko Mook, Ko Libong and the karst-strewn mainland. An offshore reef to the north has a great variety of hard coral. Such beauty, however, has not escaped the attention of day-trip boats from Ko Lanta, who often turn the beach into a lunchtime picnic ground.
Ko Kradan is known for its clear waters © Denis Costille/Shutterstock
18. For local life: Ko Sukorn
Further south than the other Trang islands, low-lying Ko Sukorn lacks the white-sand beaches and beautiful coral of its neighbours but makes up for it with friendly inhabitants, laid-back ambience and one excellent resort; for a glimpse of how the islanders live and work, this is the place to come. The lush interior is mainly given over to rubber plantations, interspersed with rice paddies, banana and coconut palms; the island also produces famously delicious watermelons.
19. For nature lovers: Ko Turatao
This is the largest of the Ko Turatao National Park archipelago and it offers the greatest natural variety: mountains covered in semi-evergreen rainforest rise steeply to a high point of 700m; limestone caves and mangrove swamps dot the shoreline; and the west coast is lined with perfect beaches for most of its 26-kilometre length.
Ko Tarutao is notable for its mountains © khlongwangchao/Shutterstock
20. For hiking: Ko Adang
This rainforest-covered island has narrow beached backed by a canopy of pines. There’s a half-hour climb to Sha-do cliff that’s worth tackling, with great views over Ko Lipe island to the south. Another option can be found near the main park station, where a 20-minute trail leads to the small Pirate Waterfall.
Explore more of Thailand's best islands with the Rough Guide to Thailand.