Viettel mandates biometric SIM verification within 2 hours of phone change in Vietnam

Vietnam's telecom regulator requires that, after a subscriber transfers a SIM to a new device, the owner must complete facial biometric verification within two hours. The rule is set out in Circular 08/2026/TT‑BKHCN and is enforced by Viettel.

If the verification is not completed, Viettel will first apply a one‑way lock (outgoing calls, messages and data blocked) after two hours, followed by a full two‑way lock after 30 days, and finally terminate the contract and reclaim the number after an additional five days.

The verification can be performed for free via Viettel’s Tammi mobile app: users log in, select “Xác thực đổi máy”, capture a portrait photo (or scan the NFC chip of the national ID card if needed), and await confirmation. Older customers or those without smartphones can visit any Viettel shop nationwide for in‑person assistance. The measure aims to prevent fraud such as OTP theft, unauthorized banking access, and social‑media account hijacking.