Most people’s first SIM in Thailand is a tourist card grabbed at the airport or a 7-Eleven. After using it for a while, they realize what they actually need is a number that can be used long-term and linked to a bank account and various other accounts. By this point, you may already be looking at housing, negotiating a lease, and preparing to open a Thai bank account, yet still unsure: where should you actually go to get a proper number, what documents besides your passport do you need to bring, is prepaid or postpaid better for a long stay, and when a store says “sure, no problem,” which conditions might later become a sticking point when linking to a bank or an app.
This article deals with just one thing: when you go to an AIS, True, or dtac store to get a Thai mobile number built for long-term use, what should you actually do, what should you ask, and which phrases should make you pay closer attention.
The Direct Answer First
If you plan to live in Thailand long-term and will later use this number to link a bank account and various services, it is advisable to go first to an official AIS, True, or dtac store or flagship store inside a major mall, rather than relying only on an airport tourist SIM or a small roadside stall. These stores are more familiar with the process for foreigners, and can handle more complex identity verification.
Under current rules, foreigners registering a SIM must always use their passport for real-name registration, and each operator imposes a limit on the number of SIMs a non-Thai user can hold, generally a maximum of 3 per operator.
Long-term residents typically start with a prepaid plan that can be topped up indefinitely, and later consider switching to a postpaid plan once they have a Thai bank account, more complete proof of address, and stable income; this keeps the initial document requirements lower and makes it easier to get a number quickly at the start.
Whether the number is correctly registered under your own passport, whether it can be kept active long-term rather than automatically expiring after 30 or 60 days, and whether it will continue to work for receiving OTPs under bank or government anti-fraud rules going forward — these matter more than which plan has the cheapest monthly fee.
An Overview of Thailand’s Main Telecom Operators: How Do AIS, True and dtac Differ?
The operators foreigners most commonly deal with when getting a mobile number in Thailand are AIS, True, and dtac. All three offer prepaid SIMs and some postpaid plans, and all have official stores, apps, and online top-up channels. What actually matters when comparing them is not just the monthly fee, but whether the store is familiar with foreigners’ documents, whether the number can be kept long-term, whether the app is easy to manage, and whether an identity mismatch could come up later when linking to a bank or receiving an OTP.
AIS: A Major Thai Operator, Good for Anyone Who Wants a Stable Primary Number
AIS is one of Thailand’s major telecom operators, offering mobile service, 5G/4G networks, prepaid and postpaid plans, home broadband, and enterprise digital services. For long-term foreign residents, AIS’s advantage is broad official-store coverage, and its mall flagship stores generally have more experience handling SIM registration, replacement, plan changes, and identity verification for foreigners.
If you plan to use this Thai number long-term as your primary contact number for banking, renting, food delivery, transport, government services, or various apps, AIS is worth including as one of your top options to compare. When applying, you can directly ask the staff: can this prepaid number be kept active long-term, can it later be converted to postpaid, and if a bank later asks to re-verify the number holder, can that be handled at an AIS store.
True: The Main Operating Brand After the True/dtac Merger, With a Broader Range of Services
True is a major Thai telecom and digital services brand, covering mobile service, 5G, home broadband, digital services, and enterprise plans. Since True and dtac completed their merger, the combined company operates under the name True Corporation Public Company Limited, so many of the True/dtac stores, products, or services you now see in Thailand already sit within the same corporate structure.
For long-term residents, True’s advantage is a large number of stores and service points, with a wide range of mobile plans, broadband, home services, and bundled offers. If you may need a mobile number, home internet, family broadband, or to manage multiple numbers together in the future, True is worth adding to your comparison list. When applying, be sure to confirm specifically whether you are buying a regular long-term prepaid/postpaid number, or a Tourist SIM only suitable for short-term visitors.
dtac: Still a Common Brand, but Note It Is Now Part of True Corporation
dtac was originally one of Thailand’s main mobile operator brands, and after merging with True, the dtac brand still appears in the market, with its own stores, app, prepaid cards, and customer service channels still operating. For some long-term residents in Thailand, dtac remains a common choice, especially for those who have used a dtac number for years, or who are used to the dtac app and top-up system.
New users should keep one thing in mind: dtac should no longer be understood as a fully separate company from True — it is now a brand still operating under the True Corporation structure. So when applying at a store, you can ask directly: for future SIM replacement, name changes, upgrades, converting to postpaid, or handling a bank OTP issue on this dtac number, do you go to a dtac store, a True/dtac store, or a specific service center?
A Practical Checklist: What to Prepare Before Going to the Store, and What to Ask Once There?
Prepare Before You Go
- Your original passport
- Your current visa or visa-exemption entry page (have your entry stamp, long-stay visa sticker, or e-visa screenshot ready)
- If you have them: a lease agreement, proof of address in English/Thai from your landlord, a work permit, an employment contract, or an employment letter from your company
- If you already have a Thai bank account: your bank card and bank app (helpful for linking later, or proving you have a local account)
Questions to Confirm Point by Point at the Store
“Will this number be registered under my own passport? Will I need facial recognition or re-verification later?” Confirms you are registered as the holder, so there are no issues later when the NBTC tightens real-name or facial-recognition requirements.
“With my current visa and documents, how many SIMs can I register? Is this a regular prepaid card, or can I also get postpaid?” Foreigners are generally limited to a maximum of 3 SIMs per operator, and in some cases only a prepaid plan may be allowed.
“How long is this plan’s number validity? If I go back to my home country every few months, how often do I need to top up so the number isn’t canceled?” This helps you avoid ending up with a tourist SIM that is valid for a maximum of 60 days and cannot be extended by topping up.
“If I later want to link this number to a bank or a government app, what extra documents will I need? Is this plan suitable?” Some banks require the number to be registered under your own name, and advise against using a tourist-type SIM.
“Can I later upgrade or convert this prepaid number to a postpaid plan? What are the conditions?” This helps you understand the upgrade threshold in advance, including whether a local bank account, a work permit, or a minimum monthly fee is required.
“Will you set up the operator’s app and language for me on the spot? Will I be able to check my usage and top up online afterward?” This makes sure you can manage the number yourself through the app later, rather than relying entirely on the store or a convenience store.
Which Answers Should Make You Cautious?
“This is a Tourist SIM, good for up to two months — worry about it later if you still need it.” A tourist SIM is generally valid for 30–60 days and cannot be extended by topping up, making it a poor primary number for a long-term resident.
“You don’t need a passport, we can just sort this out — just use this number for now.” Real-name registration has been tightened, and in most cases a passport or a legally acceptable substitute document is required; a workaround that skips this process may later fail re-verification by the NBTC or a bank.
“It’s fine to register the number under someone else’s name for now.” If the number is not in your own name, a bank may later require you to transfer it into your own name before you can use it for mobile banking or as an updated contact number — some banks already explicitly require the number to match the cardholder’s identity.
“This plan is very cheap, but it can’t be linked to a bank, and it’s not suitable for long-term use.” Focusing only on the monthly fee without asking about restrictions can easily lead you into a plan meant only for short-term tourism, or a higher-risk plan — meaning you would have to re-link every account when you eventually change numbers.
“Upgrading to a postpaid plan is easy, we can deal with that later.” Without first asking clearly about the work-permit, local bank account, minimum income, or deposit requirements, you may discover you don’t qualify only when you actually want to upgrade, leaving you to apply for a completely new number instead.
Frequently Asked Questions
Q1: I only have a tourist visa right now — can I get a number “built for the long term” directly?
In most cases, yes — you can use your passport together with a tourist visa to get a regular prepaid number, and as long as you top it up regularly and don’t let it sit unused past its validity period, the number can stay active long-term. But if you want a postpaid plan directly, many operators will require more stable proof of residence and income (for example, a long-term visa, a work permit, or a local bank account) — policies vary somewhat by operator, so it’s worth asking clearly on the spot.
Q2: If I only use a prepaid number, can it still be used later to link to a bank or government services?
What matters is whether the number is genuinely registered under your own name, not whether it is prepaid or postpaid as such. If a prepaid number is fully registered under your real name, and any facial-recognition step required by the NBTC has been completed, most banks and official services will accept it; but individual banks may prefer postpaid, or have additional requirements — when getting the number, you can first ask the operator about common practice, then confirm the details with your bank.
Q3: I plan to return to Thailand only once a year — can I keep the number active?
Yes, but you need to choose a plan that is not a “tourist SIM,” and confirm that regular top-ups will keep the number valid without it being suspended due to prolonged inactivity. Before leaving, you can pre-load enough credit in the app to cover a sufficient period, or set up small recurring top-ups; also note that operators and the NBTC generally impose a time limit on an “unactivated or unverified SIM,” and exceeding that limit may require going back to a store to re-verify your identity.
For questions about a Thai visa, long-term stay, or entry status, ask Zagdim.
*Disclaimer*
*This article provides practical guidance on what a long-term foreign resident should prepare and consider when actually going to get a mobile number built for long-term use in Thailand, compiled based on recent publicly available NBTC information on SIM real-name registration and the limit on the number of SIMs foreigners may hold. Each operator’s actual document requirements, whether they accept a specific visa or bank document, and the details of prepaid/postpaid plans may change with policy and internal risk controls; before applying, rely on the operator’s guidance on-site and official terms, and check the latest requirements with your bank or other institutions as needed.*
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Sources
- NBTC – Notification on Measures for Prevention and Suppression of Technology Crime
- True – Tourist SIM & Prepaid Package Terms
- Dtac – Tourist SIM Registration Guide
- AIS – SIM registration and long-stay customer guidance
- Bangkok Bank – Mobile banking contact number update instructions
- Thailand SIM advisory portals – Long-stay SIM and OTP usage practical summaries
