Best SIM and eSIM for Thailand: data plans, Wi-Fi and phone tips

Three routes work in Thailand: an eSIM you buy online before you leave, a physical tourist SIM from a counter at the airport or a mall, or roaming on your home plan. The right one depends on how long you stay, whether you need a Thai phone number, and whether your phone takes an eSIM at all.

An eSIM is the least friction. You install it at home, land, turn it on, and data works. There is no queue, no passport check at a counter, and no plastic to lose. It suits short trips, people arriving late at night, and anyone who mainly needs maps, Grab, LINE and translation.

A local tourist SIM from AIS or TrueMove H gives you a Thai number, which some hotels, delivery apps and public Wi-Fi logins ask for. It is also easier to top up in a 7-Eleven or a carrier shop if you stay longer than your first package. The trade-off is the airport queue and the passport registration, which is required for a local SIM.

Roaming on your home plan is the simplest of all if your carrier includes Thailand, but daily fees add up fast over two weeks. Check the price per day before you decide.

An eSIM is a digital profile, so your phone must support eSIM and be carrier-unlocked. Most recent iPhones and many recent Samsung and Google phones do; some regional models do not. Check in your phone settings before buying anything.

Look at three things on any plan: the data allowance, the validity window, and whether it is data-only or includes a Thai number. Data-only is normal for eSIMs and is fine for maps, messaging apps and ride-hailing. If you need to receive calls or SMS, you need a plan with a number, or a local SIM.

Install the eSIM at home on Wi-Fi, then leave it switched off until you land. Activating early can start the clock on a short validity window. Keep your home SIM active for bank and airline codes, and set the eSIM as your data line so you are not charged roaming by accident.

Prices change constantly and depend on the provider and the data size, so treat any figure as a 2026 estimate and compare at the point of purchase.

AIS and TrueMove H are the two carriers you will see at airport arrivals and in malls, and both sell tourist packages with data and a Thai number. Registration is required and you show your passport; this is a legal requirement, not a shop policy, so no counter will skip it.

Airport counters are open long hours and are the easiest place to buy on arrival, but they can be slow when several flights land together. A carrier shop or a mall counter in the city usually has a shorter queue. Bring your passport either way.

Top-ups are simple: 7-Eleven, carrier shops and apps all sell them, and staff will usually help if you show the phone. If you stay a month or more, a local package with a monthly cycle is cheaper than stacking tourist add-ons.

Free Wi-Fi is normal in hotels, guesthouses, cafés and shopping malls, and it is usually good enough for messaging and browsing. Public networks in some places ask for a local phone number or a passport login, which is one reason a Thai SIM can be handy even if you have an eSIM.

Mobile coverage is strong in Bangkok, Chiang Mai, Phuket and the main tourist islands, with 5G in city centres and 4G on most islands. Expect weaker signal on remote beaches, in mountain areas near the northern border, and on some boat routes. Download offline maps before long drives.

If you work online, do not rely on hotel Wi-Fi alone: speeds vary, and a data plan as backup saves a bad afternoon. Power cuts and storms can knock out both.

LINE is the app that matters locally: hotels, guides, shops and drivers use it, and many will ask for your LINE ID rather than a phone number. WhatsApp is mostly used with other foreigners. Install LINE before you arrive and set up an account.

Grab and Bolt are the ride-hailing apps, and both need data and a working number for the driver to reach you. Google Maps works well for transit and walking. Thai QR payments (PromptPay) are everywhere but normally need a Thai bank account; some tourist e-wallets and cards link to it, so check before relying on it.

Most apps and sites work normally. Gambling and some political sites are blocked, and a VPN gets around that if you need one. Keep your phone charged: heat drains batteries, and a power bank is worth packing.

Thai mobile numbers are 10 digits starting 06, 08 or 09 inside the country, and the country code is +66. If someone asks for your number, give the local format; if you are dialling in from abroad, drop the leading zero.

Keep your home SIM active for bank and airline verification codes, and make sure your bank knows you are travelling so a card is not frozen mid-trip. If you use a data-only eSIM, calls to your home number may still route over the home SIM, which can cost money; check your carrier's rates.

Before a long trip, look at the Thailand visa requirements and public holidays, since both affect how you plan days and bookings. For everything else on the ground, start from the Thailand travel guide.