If you plan to stay in Thailand longer than your holiday, check how to keep your existing phone number before the tourist phone plan expires. A SIM is the small card—or digital phone connection—that gives your phone access to a mobile network. The main networks AIS, True and dtac sell plans with different conditions. For some AIS tourist numbers, using the line beyond 60 days after activation requires a new passport identity check. True/dtac's tourist plan has a published 60-day service limit that cannot be extended by adding credit after expiry. Paying for more mobile internet alone does not settle whether the phone number itself and its registration remain active.
This matters well beyond holiday data: losing a number attached to accommodation, courier deliveries, payment records or SMS-enabled services creates extra work. A data package, a SIM/number validity period, and identity registration are three different things. Solving one does not automatically solve the others.
One problem, three clocks that should not be mixed up
| What ends? | What you actually lose or must address | What is NOT a reliable fix |
|---|---|---|
| Your data or calling package expires | Promotional GB, calling allowances or tariff benefits may stop; the SIM may still be registered and active under its own terms. | Assuming buying more data renews identity registration. |
| Your tourist SIM/service validity expires | The operator may restrict or stop that specific tourist product; preserving the exact number depends on the operator's allowed re-identification/continuation route. | Assuming a top-up after expiry guarantees the same number. |
| Your identity registration requires reconfirmation | Service may require passport or app/shop verification under the relevant operator's rules. | Ignoring a legitimate re-registration instruction just because the balance is positive. |
Concrete example: You bought a 30-day package, stay 70 days and add credit near day 30. You may have renewed some account benefits, but the 60-day tourist identity/service conditions still matter. Conversely, buying a fresh 30-day SIM could supply internet but would usually mean a different number: it doesn't preserve contact numbers already saved on accounts.
AIS: keep the Tourist SIM registered beyond day 60
The AIS official tourist page says a foreign visitor who wants to continue using an AIS Tourist SIM beyond 60 days from activation must reconfirm identity. AIS lists two routes:
- SMS route: send your passport number to 4444161, then complete verification through the link AIS returns. The official page calls the SMS free. Treat your passport number as sensitive; use the operator's stated number, not a forwarded social-media link. Read the actual reply and official domain before supplying further information.
- In-person route: visit an AIS Shop with your passport and ask for the correct tourist-SIM identity reconfirmation/continuation action. This is the practical fallback if you no longer receive verification messages or the online process fails.
AIS separately notes that a newly registered number must be activated within 60 days of its registration date or identity verification may be required again before activation. That activation deadline and the 60 days after tourist activation are not the same clock. Don't confuse one with the other.
If you bought a resident prepaid plan, postpaid plan or a special corporate SIM, these tourist-specific instructions may not be your actual contract. Confirm the exact plan and registered identity via myAIS/AIS Shop rather than applying a visitor article to every number.
True/dtac: a late top-up doesn't extend an expired tourist SIM
The current True/dtac tourist conditions are explicit: tourist package/SIM validity may not exceed 60 days, and validity cannot be extended through top-up once expired. For service after expiry, True/dtac directs the customer to re-identify with a passport at a True/dtac Shop or contact 1242 (True) / 1678 (dtac). The terms do not guarantee that every expired number is recoverable, so contact support before expiry if continuity matters.
Before day 60: determine which SIM product you really have, its current package expiry and registered number. Use the provider's service/status channel, not a random online “extension hack”. If you plan a stay longer than the tourist package was sold for, ask True/dtac about their current supported re-identification or change-to-suitable-plan process for your existing number. Do not assume ordinary credit top-ups change the legal tourist validity.
If you've already passed expiry: do not keep buying top-ups hoping the old number will automatically become active. Contact 1242/1678 or an authorised True/dtac Shop, bring your original passport, and ask specifically whether your existing number can still be recovered under its state and registration record. If the number is no longer eligible for continuation, arrange an alternative number and update the services that depended on the old one.
For a registration-document update, True's official instruction page provides status code *165*6#, a True App → Update Registration Document flow, and an authorised shop fallback. For foreign customers, the app supports passport-based document updates; other accepted document types may require a shop. True says registration-document review normally takes about seven days. This is registration-document maintenance, not proof that an already expired tourist number has been renewed.
Which action fits your real stay?
| Situation | Best next action | Risk to avoid |
|---|---|---|
| AIS visitor now staying 75 days, number still active | Start AIS identity reconfirmation before day 60 via official SMS or AIS Shop; separately arrange suitable usage package. | Treating data top-up as identity renewal. |
| True/dtac visitor approaching 60 days, still has access to SMS | Ask 1242/1678 or a shop before expiry for your exact SIM's options, with passport. | Waiting until day 61, then topping up expecting automatic continuation. |
| Traveller returning to Thailand months later, SIM has not worked recently | Verify the current number status with the original operator before relying on the old number for login or a taxi pickup. | Assuming a stored plastic SIM guarantees the number has been reserved. |
| Number already stopped and is on banking/QR accounts | Recover account access through each service's own official account-recovery route, while the operator confirms if number recovery is possible. | Buying random replacement SIMs or handing OTPs to intermediaries. |
A realistic failure: Someone has used the same Thai number for several months and receives a request to update registration. The SIM still has a positive balance, so they ignore it. Later a bank or app sends a login OTP to a number they cannot receive. The safe sequence is first identify the operator and whether the line is technically active → resolve identity/service status at the operator → use each bank/app's official recovery method if SMS is unavailable. An operator cannot override a bank's separate identity rules. Never share OTPs, PINs or remote-access codes with someone claiming to “save” a number.
Before leaving Thailand, check whether the number will work abroad
An active Thai SIM at home does not automatically include international roaming. True/dtac's tourist terms specifically say prepaid international roaming is not included in that product's standard benefits. Confirm whether the exact plan supports roaming and receiving SMS in the country you will visit; verify charges and activation before flying. A phone still showing a Thai number in contacts is not proof it will receive SMS abroad.
For a longer stay or repeat visits, consider whether an appropriately registered standard resident/prepaid/postpaid plan is supported for your identity and needs. Do not assume switching plans will preserve your number until the provider confirms it. If a Thai bank or a tourist QR payment service uses your number, get its account recovery and number-update instructions while the old SIM still works. Thai bank-account guidance covers separate eligibility and verification issues, and DTV long stays is not the same as mobile contract eligibility.
What to do this afternoon
Open the SIM's actual registered operator, purchase/activation date, current package end date and service status. Then choose the operator-specific action: AIS tourist identity reconfirmation, or True/dtac customer support/passport re-identification where applicable. Save receipts or support reference numbers, and test an inbound call and SMS when the operator confirms service. Do not wait for a missed bank OTP to discover that credit balance, number validity and identity registration were separate problems.