Thailand is one of the easiest countries in the world to stay connected in. Coverage is excellent, data is cheap, and 5G reaches further than it does in most of Europe. The only real decision is whether you buy the connection before you fly or after you land — and since May 2025 there is a new reason to lean towards “before”.
Why this matters more than it used to
All non-Thai nationals arriving by air, land or sea must now complete the Thailand Digital Arrival Card (TDAC) online before entry. You submit it up to three days ahead on the official immigration site — it is free — and you receive a QR code by email that you show at the border.
You can complete it at home on hotel wifi before you travel, and you should. But plans change, connections get missed, and the number of people standing in the arrivals hall at Suvarnabhumi trying to open an email with no data is not small. Landing already online removes that risk entirely, and it also means your ride-hailing app, your maps and your hotel booking all work from the moment the plane doors open.
eSIM or physical SIM?
An eSIM is a profile you install on the phone itself. Nothing to collect, nothing to lose, and your home number stays active for two-factor authentication messages while the data runs over the Thai plan. It works only on eSIM-capable handsets — broadly iPhone XS and newer, Pixel 3 and newer, and recent Samsung Galaxy S and Note models — and only if the phone is carrier-unlocked.
A physical tourist SIM bought at the airport is cheaper per gigabyte and comes with a Thai phone number, which some domestic services and delivery apps want. The trade-off is the counter queue after a long-haul flight, and the small ceremony of losing your home SIM in a hotel drawer for two weeks.
For a one- or two-week trip on a modern phone, the eSIM wins on convenience by a wide margin. For a month or more, or if you need a local number, the physical tourist SIM is better value.
What things cost
Airport tourist SIMs from AIS and True run roughly ฿300–450 for 8–15 days of high-speed data marketed as unlimited, with the larger packages reaching ฿1,200–1,600 for longer stays and bigger allowances. The same operators sell cheaper packages in their own city shops than at the airport desks, if you are willing to wait a day.
Travel eSIMs from international providers typically land in the US$5–20 range for 5–20GB over 7–30 days. Per gigabyte they are usually a little more expensive than a local tourist SIM; the premium buys you setup before departure and, on most of them, regional coverage across Southeast Asia on the same profile.
That last point is the real differentiator. If Thailand is one leg of a route that also takes in Vietnam, Cambodia, Laos or Malaysia, a regional eSIM that follows you across borders is worth more than the few dollars it costs over a single-country SIM — because the alternative is queueing for a new SIM in every country.
Roaming from home is the expensive default. EU “roam like at home” rules do not apply in Thailand, and pay-as-you-go rates from most Western carriers run US$5–15 per day or worse per megabyte. Check before you assume; a lot of people discover this on the bill.
The networks: AIS, True and NT
AIS has the largest network in the country and the best coverage on the islands and in rural areas. If you are heading to Koh Lanta, Koh Chang, the far north or anywhere off the main tourist spine, AIS is the safest choice.
True — which merged with dtac in 2023 — is very strong in Bangkok, Chiang Mai, Phuket and the main tourist corridors, and often slightly cheaper.
NT (National Telecom) is the state operator, cheap and adequate, and rarely the right answer for a visitor.
Most travel eSIM providers do not let you choose; they connect to whichever partner network they have an agreement with. If island coverage matters to you, look for a provider that names AIS explicitly.
Which option suits which trip
- Long weekend in Bangkok, modern phone: a small travel eSIM. Install before you fly, done.
- Two weeks, Bangkok plus islands: either an AIS-backed eSIM or an AIS tourist SIM bought at the airport. Coverage beats price here.
- Multi-country Southeast Asia route: a regional eSIM covering the whole itinerary.
- A month or more, or working remotely: a local physical SIM on a monthly package, topped up in any 7-Eleven.
- Older or carrier-locked phone: physical SIM. The eSIM question does not arise.
- Family or group: one person on a plan with hotspot allowance can often cover everyone, which is cheaper than four separate plans. Check that tethering is permitted — some cheap plans block it.
You will find our current eSIM partner offer in the sidebar of this page; it is the option we point people to for a straightforward single-country or regional plan.
Setting up an eSIM without drama
- Check the phone is eSIM capable and unlocked before you buy anything. On iPhone: Settings → General → About → look for an EID. On Android: Settings → About phone → look for an EID or an “Add eSIM” option.
- Install on wifi at home, a day or two before you fly. Installation needs a data connection, which is the one thing you will not have on arrival.
- Do not delete your home SIM. Keep it as the primary line for calls and SMS, and set the Thai eSIM as the data line.
- Turn off data roaming on the home line once you land, or you will pay for both.
- Keep the QR code — most providers only let you install a profile once, and reinstalling on a new phone means buying again.
Coverage in Thailand is genuinely good: 5G across Bangkok, Chiang Mai, Phuket, Pattaya and most provincial capitals; solid 4G almost everywhere else. The gaps are in national parks, on the smaller islands and in the mountains along the Myanmar border.
What you will actually use the data for
More than you expect. Grab and Bolt for transport, and both are meaningfully cheaper and less stressful than negotiating with a taxi. Google Maps, constantly, because Bangkok addresses are close to unusable without it. Translation, because outside tourist areas English is limited. LINE, which is how Thailand messages — hotels, tour operators and drivers will all ask for your LINE rather than your email.
Ten gigabytes over two weeks is comfortable for most people. Twenty if you are streaming or hotspotting a laptop.
Practical notes
- Register your SIM. Thai law requires SIM registration with a passport. Airport and official shop purchases handle this for you; a SIM bought from a market stall may not be registered, and unregistered SIMs get cut off.
- The TDAC is free. The only official site is the immigration department’s own. Third-party sites charging a “processing fee” are not required and not endorsed.
- Wifi is everywhere — hotels, cafés, malls, most restaurants — and is usually fast. Your data plan is for the gaps, not for everything.
- Top-ups for local SIMs are sold in every 7-Eleven and Family Mart, which is to say roughly every 200 metres.
- Keep a screenshot of your hotel address in Thai script. It solves more taxi problems than any app.
Further reading
- Things to do in Bangkok — including why the Grand Palace has no train station
- Bangkok airport transfer guide
- Domestic flights in Thailand
- Scooter rental in Phuket
Prices, network details and the TDAC requirement were checked in August 2026 and change — confirm on the operator’s and the Thai immigration department’s own sites before you travel. Some links on this page are affiliate links; if you book through them we may earn a commission at no extra cost to you.
Add comment