VoLTE and the 2G/3G switch-off: will your phone still make calls?

How calls travel · Published 2026-10-24

For decades, mobile voice calls ran on 2G and 3G networks even when your data used 4G. As operators retire those older networks, voice has to move to VoLTE, voice over 4G. Phones that cannot do VoLTE on your operator's network lose the ability to make ordinary calls.

What VoLTE is

4G (LTE) was designed as an all-IP network: it has no circuit-switched voice channel like 2G and 3G. Early 4G phones handled calls by dropping back to 3G or 2G for the duration of the call, a technique called circuit-switched fallback. VoLTE (Voice over LTE) instead carries the call as VoIP across the 4G network, managed by the operator's IMS core and set up with SIP, the same protocol described in our guide to how VoIP works. The GSMA's IMS profile for voice over LTE (document IR.92) defines the minimum features that phones and networks must support so that they interoperate.

Compared with fallback, VoLTE brings faster call set-up, the ability to keep using 4G data during a call, and usually HD Voice with wideband codecs such as AMR-WB or the newer EVS. On 5G standalone networks the equivalent is VoNR (Voice over New Radio).

Why 2G and 3G are being switched off

Radio spectrum is limited and expensive. Each old network that stays on occupies frequencies that could carry far more traffic as 4G or 5G, and requires its own equipment, maintenance and energy. Operators in many countries have therefore announced or completed the shutdown of 3G, and in a number of countries 2G as well. In the United States, the major operators completed their 3G shutdowns in 2022. In Europe, timetables are set operator by operator and country by country, and some operators keep 2G running longer than 3G because it still serves older machines, alarms and basic phones.

Because dates differ and change, the only reliable sources are your operator's announcements and the national regulator. Regulators such as the FCC in the US have published consumer information on the 3G shutdown (FCC guide).

Which phones are affected

• Phones without 4G. Older basic phones and early smartphones that only support 2G/3G will lose service when the network they rely on is switched off.
• 4G phones without VoLTE support on your network. This is the less obvious group. A phone can have 4G for data yet be unable to make VoLTE calls on a particular operator, because VoLTE requires operator-specific configuration and certification. Imported phones and some older or cheaper models fall into this category. Once 3G and 2G are gone, such a phone may show 4G signal but fail to make or receive calls.
• Devices that are not phones. Alarm systems, personal emergency pendants for elderly people, lift emergency phones, payment terminals and car emergency-call modules can rely on 2G or 3G. Their owners should ask the supplier whether a replacement is needed.

How to check your phone

1. Look for "VoLTE" or "4G calling" in the phone's mobile network settings. On many Android phones the option is under mobile network settings; on iPhone, VoLTE options appear under Settings › Mobile Data (or Cellular) › Options, where the operator supports it.
2. Check your operator's list of VoLTE-compatible devices, usually published on its support pages.
3. Make a call and look at the network indicator: if it stays on 4G (or 5G) during the call, VoLTE is working. If it drops to 3G or H+, the call is using an older network.
4. Keep the phone's software up to date; operators and manufacturers add VoLTE support through updates.

Many operators also contact customers whose devices will be affected; take such messages seriously, but verify them through the operator's official channels, as switch-offs are also a pretext for scams.

Roaming and VoLTE

VoLTE when roaming depends on agreements between your operator and the foreign network. If those are not in place and the visited country has shut down 3G and 2G, a phone may have data abroad but be unable to make regular calls. In that situation, Wi-Fi calling or app calls are the fallback. Ask your operator whether "VoLTE roaming" is available in your destination before travelling, especially to countries that have retired their older networks.

Emergency calls

Emergency calls follow the same logic: a phone that cannot use VoLTE on any available network may be unable to reach emergency services after a switch-off. This is one of the reasons regulators and operators have pushed for older devices to be replaced. See emergency calls over VoIP and Wi-Fi.

Helping a relative

If an older family member uses a basic phone, check the model against the operator's compatibility list well before the switch-off date. Simple 4G feature phones with large keys exist; make sure the one you choose explicitly supports VoLTE on the relevant operator, and test a call before handing it over. Do the same for any emergency pendant or alarm that uses a SIM card.

In short

• VoLTE is voice as VoIP over 4G, run by your operator.
• Once 2G and 3G are gone, a phone needs working VoLTE on your network to make ordinary calls.
• "4G" on the box is not enough: check your operator's VoLTE device list.

For other compatibility questions, see what makes a phone work well for calls.