Island living in Thailand, in figures rather than adjectives.

The four islands, and the scale nobody quotes correctly

Start with size, because it is the one thing that is actually measured and the one thing guides get wrong. Koh Samui City Municipality publishes the figures for its own island: 227 square kilometres, or 142,031 rai. The municipality itself covers about 252 sq km (157,273 rai), because its boundary takes in 18 further islands around Samui. And on the same page the municipality states, flatly, that Samui is Thailand’s third-largest island, after Phuket and Koh Chang — not second, which is what a great deal of published travel copy says.

Population is harder, and we are going to be honest about why. The municipality gives a registered population of 68,698, dated 5 March 2021, and adds that the unregistered resident population runs at roughly three times that. The same page puts visitors at about 3,000 Thai and foreign tourists a day, a number that looks low set against Samui airport’s traffic. We reproduce both as published rather than adjusting them, and we are not going to invent a 2026 figure.

Land use tells you more about daily life than population does. On the municipality’s numbers, agriculture is still the largest single use of Samui: 66,306 rai of coconut and 12,463 rai of durian. Significant forest survives in only two reserves, at Hin Lat waterfall and the Na Muang waterfall park. Housing and commerce ring the coast, with the administrative and tourism-business centre at Nathon on the west side and the densest development on the north and south-east coasts, in the Maenam, Bo Phut and Maret sub-districts. If you are choosing between those names on a map, the best areas to live in Koh Samui guide takes them one at a time.

Only one of these islands has a road to it

Phuket is joined to the mainland at Phang Nga by road. Koh Samui, Koh Phangan, Koh Tao and Koh Lanta Yai are not. That is not a scenic distinction, it is the whole logistics model: on Phuket a removal lorry from Bangkok reaches your door, and everywhere else your sofa, your car, your washing machine and every pallet of building material crosses on a ferry with a published tariff. Most of the “island premium” people notice at the supermarket till is that crossing, repeated.

Here is what the ferry operators themselves publish for the Gulf crossings, which is the leg most people actually use:

Two practical notes that follow from those tables rather than from anyone’s opinion. Vehicles are charged separately by size on every operator, so “bringing the car” is a recurring line in an island budget, not a one-off. And Samui is served by several piers, not one: Lomprayah alone lists Pralarn, Bang Rak and Nathon, which is why a fare quoted to you may be for a pier on the wrong side of the island from the house you are viewing.

Seatran publishes a call centre on 1381, staffed 04:00–19:00. If you are working out the whole door-to-door chain rather than one leg, the Thailand airport guide and domestic flights in Thailand cover the air half of it.

Who owns the airport, and why it shows up in your life

Phuket International is run by Airports of Thailand, and AOT publishes its own numbers. It is the only airport on Phuket island handling both domestic and international flights, and AOT ranks it Thailand’s third busiest after Suvarnabhumi and Don Mueang. The international terminal is 73,103 sq m and the domestic terminal 30,339 sq m; both operate 24 hours. The site runs to 2,238,800.35 sq m with a single runway, five aprons totalling 168,600 sq m, and 38 aircraft parking bays — 11 contact gates and 27 remote stands. AOT states the expansion under way will lift capacity from 12.5 million to 18 million passengers a year by 2029.

Samui works differently, and the difference is structural rather than cosmetic. Bangkok Airways describes Samui Airport in its own investor material as “a privately owned, public-use airport”, developed by the airline, which also owns Sukhothai and Trat. So Samui’s air link is a private asset with a single developer behind it rather than a state-run one with a published national capacity programme. Residents feel that in route choice and in fares. We are not going to put a percentage on it, because we have not found a figure we can stand behind — but if you are comparing the two islands on cost, that ownership fact belongs in the comparison, and the Phuket versus Koh Samui guide is where we set them side by side.

Koh Phangan and Koh Tao have no airport at all: the practical route is a flight into Samui or Surat Thani and then a boat. Koh Lanta has none either, and works off Krabi.

Koh Lanta: the bridge is approved, not open

This is the single most misreported thing about Lanta, so here is the state of it as carefully as we can put it. The Department of Rural Roads project connects Koh Klang sub-district on the mainland to Koh Lanta Noi, in Koh Lanta district, Krabi. Its published design is 2,240 metres in total — 1,825 m of bridge plus 415 m of approach roads — carrying two 3.75-metre lanes in a 13.5-metre overall width, using extradosed and balanced-cantilever spans. The budget is 1,849.50 million baht.

The status is where it gets untidy. The DRR’s own project site still describes the scheme as awaiting cabinet authorisation, with a 2023–2025 construction window and completion “within 2026”. Thai trade press, separately, reported the Ministry of Transport preparing to sign the construction contract on 31 August 2026, with the crossing in service in 2029. Those two accounts do not agree, and we have not been able to reconcile them against a dated DRR announcement. So: treat 2029 as projected, not fixed, and treat the mainland leg as a vehicle ferry until you have driven across a bridge yourself.

What already exists is the crossing between Koh Lanta Noi and Koh Lanta Yai, which is a bridge. It is the mainland leg that still floats. If you are weighing Lanta, the province around it matters as much as the island — see the Krabi living guide and the Koh Lanta cost of living tables.

Land title on an island, and why it is not a mainland question

Here is the most useful number on this page, and almost nobody publishes it. Koh Samui’s municipality lists the title documents issued across the island:

• Chanote (full title deed) — 42,274 plots, 72,625 rai 2 ngan 76.2 sq wa.
• NS3 Ko certificate of use — 10,017 plots, 18,038 rai 3 ngan 31.3 sq wa.
• NS3 certificate of use — 1,467 plots, 4,992 rai 1 ngan 35.8 sq wa.
• State land (NSL) — 53 plots.

Set the chanote figure against the island’s 142,031 rai and a little over half of Samui by area sits under a full deed — that is our arithmetic on the municipality’s own published figures, not a claim of theirs. The remainder is on lesser instruments, and an NS3 or NS3 Ko is not a chanote wearing a different hat. On the mainland you can often assume your way past this. On an island you cannot, because the mix is genuinely different.

We are not going to explain Thai land law on a lifestyle page. The pages that do it properly are Thai title deeds and the chanote, title deed encumbrance checks, whether foreigners can own land in Thailand and, for the apartment route, foreign condo ownership and the foreign ownership quota. BAANLYY is a listing portal and is not a law firm; a Thai lawyer reads the deed, not a website.

The 90-day report, from a place with a ferry timetable

This is the piece of island admin that catches people, and the Immigration Bureau publishes the rule clearly enough that we can quote it rather than paraphrase. A foreigner staying more than 90 days must notify, and the filing window is 15 days before, to 7 days after, the 90-day period expires. It can be done in person, by an authorised representative, by registered post, or online, with exceptions such as a change of passport. Filing late attracts a 2,000 baht fine. A foreigner arrested for not having reported at all is fined 5,000 baht. The bureau also notes that a first extension-of-stay application does the job of the notification.

On the mainland the choice of method is a convenience. On an island it is a day of your life, because the office covering your address may be across water and the postal and online routes may be the only sane ones. Work out which office serves you before your first deadline — immigration offices in Thailand and TM30 and 90-day reporting go through it, and the 90-day reporting guide covers the filing itself.

One thing we did not confirm and therefore do not print: which office covers each island, and its hours. The Phuket immigration site failed a certificate check when we tried to read it during this run, and we would rather leave a gap than publish an address that sends someone on a ferry to the wrong building.

Healthcare: check the hospital, not the island

Joint Commission International publishes its own directory of accredited organisations, and it lists Bangkok Hospital Phuket (IHCO ID 60000444) and Bangkok Hospital Siriroj, both on Phuket. That is the firm part.

The honest part: we tried to load the directory filtered to Thailand during this run and the site returned a maintenance and bot-verification page, so we have not been able to check whether any hospital on Koh Samui, Koh Phangan, Koh Tao or Koh Lanta appears on it. We are not going to assert either way, and we would treat any page that does without naming its source with suspicion. What is not in dispute is the gradient: Phuket has the deepest private provision of the four islands here, and the smaller the island the more a serious case means a transfer by boat or by air.

Compare the specific institutions rather than the island: international hospitals in Phuket, international hospitals in Koh Samui, and health insurance in Thailand — on an island, evacuation cover is not an optional line in the policy.

Choosing between the four, on the facts above

• Phuket — the only one with a road link, the only one with an AOT airport, and the only one of the four with hospitals we can point at in the JCI directory. Its own province, and the island the rest are measured against. Start with living in Phuket, best areas to live in Phuket and Phuket cost of living.
• Koh Samui — Surat Thani province, 227 sq km, a privately owned airport, a ring of coastal settlement around an agricultural interior, and a land-title mix that rewards care. See the Koh Samui living guide, moving to Koh Samui and Koh Samui cost of living.
• Koh Phangan — no airport; the route in is Samui or Surat Thani plus a boat, and Raja publishes the Donsak crossing to Thong Sala at 270 baht and about 2h30. Cheaper than Samui, thinner on services. See Koh Phangan cost of living.
• Koh Lanta — Krabi province; a bridge to Lanta Noi, a ferry to the mainland, and an approved 2,240-metre crossing that is not open. See Koh Lanta cost of living.
• Koh Tao — small, dive-led, reached by catamaran; Lomprayah runs it alongside Koh Nangyuan, Chumphon and the Samui piers. Realistic as a specialist or part-time base rather than a full-service home.

Still choosing between a coast and a city? Where to live in Thailand puts the mainland bases beside these, and Explore Thailand is the front door to the rest of it.

What this page does not claim

An island page is easy to pad and hard to source, so here is the ledger, openly:

• Phuket’s official area and population — not printed. The provincial website returned a bot-verification page and the Ministry of Commerce provincial profile carries history rather than statistics. We would rather leave the figure out than take it from an aggregator.
• Island national park entrance fees — not printed. The Department of National Parks fee page was behind a security service when we tried it. National parks in Thailand carries what we have confirmed elsewhere.
• Rents — not printed here. We have not researched island rents to this page’s standard in this run; the per-island cost-of-living guides linked above are the place for them.
• Internet speeds by island — not printed. We found no operator or regulator figure broken out by island that we could stand behind, and the honest advice is unchanged: confirm the specific property’s line before you sign. See home internet and broadband and SIM cards and mobile data.
• Sea conditions and ferry cancellations — described, not quantified. Sailings are restricted in heavy weather by the harbour authorities, and the weather and seasons and flooding and monsoon guides carry the seasonal picture. We have not published a wave-height threshold because we could not source one to the standard this page is holding itself to. For the water itself, beaches and water safety has the numbers that do exist.

Island living in Thailand: common questions

Narrowed it down? These go further on specific islands, budgets and the move itself.