Vietnam 2G shutdown could silence some 4G phones

Photo courtesy of Tuoi Tre

Vietnam will shut down its 2G mobile network nationwide from September 15, but some older and imported 4G smartphones could also lose the ability to make and receive calls unless they support Voice over LTE.

Why a 4G phone may still lose calls

Some handsets use 4G only for mobile data. When users place or receive a call, the phone quietly switches its voice connection back to 2G, a process that is normally invisible to the owner.

Once the 2G network is removed, voice calls must run directly over 4G using Voice over LTE, or VoLTE. A phone without VoLTE support may continue browsing the web, using social media and streaming video while being unable to handle ordinary calls.

People with older smartphones, imported devices and models not officially distributed in Vietnam face the greatest risk. Several operators have already started decommissioning 2G base stations in areas ready for the transition, so some disruption could occur before the official deadline.

Check the phone and SIM first

Telecommunications experts say users should not immediately buy a replacement handset. The first step is to check the phone’s mobile-network settings and enable VoLTE or 4G Calling.

On iPhones, the option is generally found under Settings, Cellular, Cellular Data Options, then Voice & Data. Samsung users can look under Connections and Mobile Networks. Oppo, Realme, Xiaomi, Redmi, Nokia and other Android phones usually place the option within SIM or mobile-network settings, although menus vary by model.

A compatible 4G or 5G SIM is also required, and the subscriber’s operator must have activated VoLTE voice service. Enabling the handset option alone may therefore not be enough.

Operators can test incompatible devices

If calls still fail after VoLTE is switched on, users should take both the phone and SIM card to their mobile operator. Staff can check compatibility, adjust settings or advise on device-transition programmes.

The 2G shutdown will free radio frequencies for 4G and 5G services and is expected to improve data capacity and call quality. Operators are urging customers to check now rather than wait until September 15.

What it means for foreigners in Vietnam

Foreign residents using imported phones or overseas SIM configurations should check VoLTE compatibility early. A 4G symbol does not confirm that voice calls use 4G, so testing outgoing and incoming calls with the Vietnamese operator is the safest approach.

2 September 2026