Thai SIM Cards Explained: Networks, Plans and Registration
Your Thai phone number does more than make calls. Banks, delivery apps, ride-hailing and government services all tie to it, so it pays to set it up properly from the start.
The short version
- Thailand’s networks are AIS and True (which merged with dtac in 2023 and still sells both brands), plus state-owned NT.
- Register with your passport. Foreigners can hold up to three SIMs per operator.
- Tourist SIMs last up to 60 days with no top-up extensions; staying longer means a monthly plan.
- Banks increasingly check that your number is registered in your passport name, so register it to yourself.
- Keep the same number long-term: it becomes your login for banking and most apps.
Who you can buy from
There are three main mobile operators. AIS is the largest, True Corporation was formed by the merger of True and dtac completed on 1 March 2023 and still sells under both brands, and state-owned NT runs the smallest network. All three have shops in malls and airports and sell prepaid and postpaid plans.
Coverage is good in the cities. If you live in the countryside or on an island, ask neighbours which network works best there before you commit.
Tourist, prepaid or postpaid?
Rules published in the Royal Gazette in August 2025 tightened registration: you show your passport, foreigners may register up to three SIMs per operator, and tourist SIMs cannot be extended past 60 days.
- Tourist SIM: quick to set up at the airport, valid up to 60 days, no extension
- Prepaid monthly: top up as you go, no contract, easy for most expats
- Postpaid: a monthly bill, often more data, sometimes a minimum term
Why registration matters for banking
Thai banks send verification codes by text and, according to 2026 reports, increasingly check that the phone number is registered in the same name as your passport. A SIM registered to a friend, agent or landlord can stall a bank application, so register it to yourself from the start and keep it.
SIM mistakes to avoid
It cannot be extended past 60 days.
Banks may reject it.
Your number is your login for banks and apps.
Lost numbers can mean locked accounts.
Everything on getting connected
Related guides from the JLIT library.
Hubs for getting connected
Plans, broadband and what comes next.
Keep going
Questions newcomers ask
Which mobile networks are there in Thailand?
AIS, True (which merged with dtac in March 2023 and still sells both brands) and state-owned NT.
How long does a Thai tourist SIM last?
Up to 60 days. Under the August 2025 rules it cannot be extended by topping up, so long-stayers need a monthly plan.
How many SIM cards can a foreigner register?
Up to three per operator, registered with your passport.
Do I need a Thai number to open a bank account?
In practice yes. Banks send verification codes by text and increasingly check the number is registered in your own name.
