Do I need to re-register my Vietnamese SIM card and what happens if I miss the deadline?
Based on 2 discussions with 3 participants · Last activity: today
TL;DR
Vietnam is rolling out mandatory SIM re-registration with face verification at carrier offices. If your SIM is linked to a bank, Zalo, or Grab, don't delay. Also, fully disable your home SIM before arrival to avoid surprise roaming charges.
What the community said
Vietnam is conducting a nationwide SIM re-registration campaign requiring in-person visits to carrier offices, face scanning, and updated passport details — for both locals and foreigners. If your number is linked to a bank account, Zalo, or Grab, losing access could cause serious disruption. If you're abroad for several months, check your carrier's deadline before returning.
4 days ago SIM re-registration: carrier office + passport + face scan required
Before arriving in Vietnam, fully disable your home SIM in your phone settings — not just airplane mode, but actually turning the SIM off. Even if you ignore calls and texts, your phone can automatically connect to a local network and your carrier will bill you for roaming. A single missed call is enough to trigger charges.
6 days ago Disable home SIM in phone settings to avoid roaming charges
Topping up a Mobifone SIM via the official website may return an 'Invalid phone number' error even after successfully logging in — a known site issue. Alternatives include using the My MobiFone app, visiting a carrier store in person, or buying a top-up scratch card at any convenience store.
10 days ago Mobifone top-up: use My MobiFone app or visit a store