Buying a SIM card at the airport: what the counter will ask for

Before you reach the counter

Check that your phone is unlocked. A phone tied to your home operator will not work with a local SIM, and the airport shop cannot fix that for you. Our guide on how to check if your phone is unlocked takes a minute and saves the trip back to the counter.

Then decide where your own SIM will go. On a phone with one slot it has to come out, and it is small enough to lose on a tray table. Bring a SIM pin or a paper clip and somewhere safe to keep it. Ask the seller three things before paying: whether the plan includes a phone number or only data, how long it lasts, and how you top it up once you leave the airport.

Thailand: passport, in person

Thailand's telecom regulator, the NBTC, requires SIM cards to be registered to the user. Under its current rules for people without Thai nationality, the passport is the main identity document, registration is done in person at an operator's branch or an authorised dealer, and each foreigner can hold at most three SIMs per operator.

In practice that means the counter in the arrivals hall will take your passport and register the SIM before activating it. Keep the passport within reach as you leave immigration, not packed in a suitcase. If you would rather skip the counter, our Thailand eSIM is installed before you fly, and our guide to internet in Bangkok covers what to expect at Suvarnabhumi and Don Mueang.

India: passport, visa and a local address

India's Department of Telecommunications sets the verification rules for foreign visitors. Its instructions accept a copy of your passport with a valid visa as proof of identity. For proof of address, the seller takes a local reference, which can be your tour operator, or, if you have none, the address where you are staying, such as your hotel.

The connection is also tied to your visa: it cannot stay valid beyond the visa period. So have the hotel address written down, keep a copy or photo of your visa page, and expect the process to take longer than a quick card swap. If you land late at night, that matters more than the price.

Turkey: the SIM is the easy part, the phone has a deadline

Turkey adds a rule about the phone itself. According to the telecom regulator, BTK, phones brought from abroad by a traveller have to be registered within 120 days of the traveller's entry into the country to keep working on Turkish networks. Registration means paying a fee and linking the phone's IMEI, which you can see by dialling *#06#, and it is not possible if you have already registered another phone from abroad in the last two calendar years.

For a normal holiday this never comes up, because you leave well before the deadline. It matters for long stays, students and remote workers, who should plan for it from the start. Our Turkey eSIM page and the guide to internet in Istanbul cover the shorter trips.

What tends to go wrong at the airport

• The phone turns out to be locked, and you find out after paying.
• Your own SIM comes out and you stop getting bank codes and calls on your number.
• You leave without testing it, and data does not work once you are in the taxi.
• The plan instructions are only in the local language and you cannot find how to top up.

Test the SIM before you walk away: open a web page with wifi switched off. And if your own SIM had to come out, read how to get bank SMS codes abroad before you need one.

The option without a queue

If your phone supports eSIM, a data eSIM bought online skips the counter entirely. You install it at home with a QR code, your own SIM stays in the phone for calls and texts, and the plan connects when you land. With Snoozim it only starts counting at that first connection, so installing it early costs you nothing.

What a data eSIM does not give you is a local phone number. If you need one, the counter is still the way to get it. You can check whether your model supports eSIM on our compatibility page.