The 850 MHz spectrum, operated by True in partnership with NT (National Telecom Public Company Limited), will reach the end of its contract on August 3, 2025. True confirms that there will be no issue of SIM deactivation. This is because True has other spectrum bands available to fully support service coverage, including 700 MHz, 900 MHz, 1500 MHz, 1800 MHz, 2100 MHz, 2300 MHz, 2600 MHz, and 26 GHz. To ensure a smooth transition, True has already facilitated automatic SIM upgrades for customers using 850 MHz. Almost all customers have already been upgraded, and only a few phone numbers still use SIMs that do not support automatic upgrades, such as those used with certain IoT devices.
However, True 850 MHz customers who have not yet upgraded their SIM can still use their services normally within Thailand, and there will be no SIM deactivation. True recommends upgrading to a new SIM card for the best signal performance and seamless usage, especially if you plan to use international roaming.
2 easy ways True customers can check if their SIM is an 850 MHz SIM that needs an upgrade:
- Dial *850# (when checking the SIM from the mobile phone currently using it).
- Dial *850* followed by the 10-digit phone number you want to check, then press # and call (for checking the SIM used in another mobile phone or device).
The system will send an SMS response with status information as follows:
- No action needed: ” Your SIM can be used continuously. No further action is needed. Thank you for choosing True.”
- SIM upgrade required: ” Your SIM card must be changed urgently to ensure uninterrupted international roaming service after 850 MHz contract expires on 3 Aug’25. Please bring your SIM and ID card/Passport to True Shop. For business customers, please provide additional documents, such as an employee ID card or proof of employee identity.”
How True 850 MHz customers can upgrade their SIM for a smoother experience
For True customers who need to upgrade their SIM, the company has prepared multiple service channels. Customers who upgrade to a new SIM will retain all their benefits and can continue using their current package.
Upgrade options:
- Visit any True Shop
Bring your national ID and current SIM card to receive a free new SIM, with assistance from staff at any True Shop, dtac Shop, or TrueSphere nationwide. - Call 1242
Request a new SIM to be delivered to your home, along with step-by-step guidance for replacement. - eSIM customers
Easily upgrade by yourself via the True Application by selecting the “Change/Upgrade eSIM” menu.
If you have any further questions, please contact the True Call Center at 1242.
