The problem of a lost signal in remote areas of the city, a country house, or a basement office is familiar to every smartphone user. It often happens that the network indicator shows a single bar or even a crossed-out circle, making it impossible to make or receive an important call. In such situations, Voice over IP technology comes to the rescue, allowing you to use your internet connection for voice communications.
Modern smartphones and telecom operators have long ago introduced a function that allows make calls via WiFi Without loss of connection quality. This solution eliminates the need to run around the apartment looking for a spot with the best signal or go out onto the balcony. The technology works transparently for the subscriber: you dial the number as usual, but the connection goes through the router's wireless network, bypassing cellular base stations.
In this article, we'll cover in detail how to activate this feature on different devices, which carriers support it, and how to save on international calls. You'll learn the technical nuances of VoWiFi and enjoy a stable connection even in places where your phone would previously be rendered useless.
What is VoWiFi and how does it work?
The technology in question is called in the professional community VoWiFi (Voice over WiFi). This standard, developed by the GSM Association, enables the transmission of voice packets over the internet using the IP protocol infrastructure. Unlike popular messaging apps, which require both parties to install a separate app, VoWiFi is integrated directly into the standard smartphone dialer.
The principle of operation is that the voice signal is digitized, packaged into IP packets, and transmitted through the router to the telecom operator's network, from where it is routed to the subscriber. To the user, it sounds like a regular call, but the sound quality is often higher thanks to HD Voice codecs, and the coverage area is limited only by the range of your access point. The key difference from instant messaging apps is that you use your real phone number and are charged according to your standard tariff plan, rather than using your internet traffic.
It's important to understand that this feature requires support from three components: your smartphone, your SIM card (or eSIM profile), and your carrier. If even one component doesn't support the technology, you won't be able to activate WiFi calling. Your carrier must have configured gateways to route voice traffic from the internet to their telephone network.
VoWiFi is especially useful in buildings with thick walls, where the cellular signal weakens, but where a powerful router is installed. This allows for voice communications to be provided to entire office buildings, underground parking garages, and remote summer cottages.
Checking smartphone and operator compatibility
Before setting up, make sure your equipment and data plan are ready for voice over internet. Not all phone models, even modern ones, have hardware or software support for this feature in a given region. The list of compatible devices is constantly expanding, but older models may not have the required module.
Additionally, telecom operators may restrict access to the service depending on the SIM card's registration region or plan type. For example, corporate plans sometimes require separate activation by the administrator. It's also worth checking that your device's software is updated to the latest version, as VoWiFi support is often added with security patches.
Below is a table of the main operators and their technology support in various regions, which will help you navigate service availability:
| Operator | Android support | iOS support | Peculiarities |
|---|---|---|---|
| MTS | Full | Full | Profile update required |
| Megaphone | Full | Full | Works in roaming |
| Beeline | Full | Full | Activation is required in your personal account. |
| Tele2 | Full | Full | Auto-activation on new tariffs |
It's worth noting that even if the operator claims support, in some remote regions, gateways may not be configured or may be unstable. In this case, the phone will attempt to establish a connection, but the call may be dropped or not connect at all.
⚠️ Attention: Operator settings interfaces and plan terms are subject to change. If you don't find the option to enable it in the menu, check your operator's official website or contact support, as the list of supported phone models is updated regularly.
Setting up WiFi calling on Android
On Android, the activation process may vary depending on the smartphone manufacturer and operating system version. Engineers at Samsung, Xiaomi, Google, and other brands implement access to network settings differently. However, the general procedure remains similar for most devices.
First, you need to make sure your phone's Wi-Fi is enabled and connected to a network. Then, go to the main system settings. The path might look like this: Settings → Connections → Wi-Fi Calling or Settings → Mobile Network → Wi-Fi CallingOn some models, the icon may be called "Wi-Fi Calling".
After turning on the slider, the system may request confirmation of your address for emergency services (E911). This is standard procedure, required by law in many regions, as calling online can make it more difficult for operators to determine your exact location. Please enter your current residential or registered address.
If you can't find the item you need in the menu, use the settings search. Enter "WiFi" or "Calls" in the search bar, and the system will automatically suggest the desired option. Some firmware versions require prior activation of the service via a USSD code or the operator's app.
For smartphone owners Samsung Galaxy And Xiaomi Often, additional verification is required in the engineering menu or through the phone app. In the dialer, tap the three dots in the corner, select "Settings," and look for the switch there.
☑️ Check before enabling VoWiFi
Instructions for iPhone (iOS) owners
Ecosystem users Apple values unified interfaces, and VoWiFi setup is extremely simple and consistent across all models, starting with the iPhone 5C and newer. However, as with Android, the availability of the menu item depends on whether your carrier's iOS is recognized and supports the technology in your country.
To activate the function, go to the menu Settings → CellularIf you have two SIM cards (a physical one and an eSIM), select the one you want to configure. Next, find "Wi-Fi Calling" and toggle the switch to on. The system will notify you about sharing your location data with emergency services.
Also available in this menu is the "Add Other Devices" option. If enabled, you can receive calls on your iPhone even when it's in another room, but close to an iPad or Mac connected to the same Wi-Fi network and using the same Apple ID. This is extremely convenient for multitasking.
Sometimes, after enabling this feature, you may see "WiFi" appear in the status bar next to your carrier's name. This indicates that your phone is ready to make internet calls. If the icon doesn't appear, try restarting your device or reconnecting to the Wi-Fi network.
Roaming pricing and savings
One of the most important questions for travelers is how much Wi-Fi calls cost. This is where the technology's main economic rationale lies. When you're roaming (in another country) but connected to a local Wi-Fi network, calls to a number in your home region are often charged as regular incoming or outgoing calls in your home region, without roaming rates.
Technically, the call goes over the internet to the operator's gateway in your country, so as far as the network is concerned, you appear "at home." However, the rules may vary between providers. Some operators may still charge roaming rates for minutes used, even if the connection is via WiFi, so critical clarify this point before the trip.
Incoming calls over WiFi while roaming are free with most major carriers, as the traffic goes over the internet, not through partner networks abroad. This allows for significant savings while abroad. Just remember to turn on airplane mode and activate WiFi only, so your phone doesn't accidentally register with the local network and start using your background data plan.
For domestic calls, the rate is typically based on your base plan. Minutes are used from the bundle included in the subscription fee. If the bundle is exhausted, the standard per-minute rate applies.
Troubleshooting and connection quality
Despite its convenience, VoWiFi technology can have its challenges. Users most often complain of choppy sound, echo, or voice lag. This is directly related to the quality of the internet connection. A stable connection requires low latency (ping) and sufficient bandwidth.
If the audio quality is poor, try moving closer to the router. Problems can also occur if the WiFi network is overloaded with other devices actively downloading files or watching 4K videos. In this case, the router's voice traffic priority (QoS) may not work, causing calls to drop.
Another common issue is the inability to switch between WiFi and cellular networks. If you move out of range of the router during a call, the call may be dropped, as seamless handover is not supported by all carriers and phone models. Ideally, the phone should automatically switch to LTE/5G, but in practice, you often have to return the call.
Why does the call disconnect when I leave the house?
The technology for transferring calls between different network types (WiFi and GSM/LTE) is called handover. If your carrier or phone doesn't support the VoWiFi-to-LTE handover standard, the connection will be lost when the WiFi signal is lost. This is a technical limitation that can only be resolved by upgrading your carrier's network equipment.
Security and privacy
Using open Wi-Fi networks in cafes, airports, and hotels for voice calls carries certain risks. Although the voice traffic itself is encrypted by the operator in the VoWiFi standard, the setup signals are transmitted over a public network. Attackers on the same network could theoretically see that you're using VoWiFi, although deciphering the conversation would be extremely difficult.
However, for confidential conversations, it's best to use trusted home networks or a corporate VPN. Public hotspots often don't provide adequate data security. If you must call over public WiFi, ensure the connection is secure or use additional encryption.
It's also worth remembering location privacy. When you first enable the feature, your phone transmits your address to emergency services. This data is stored by the operator and can be used to determine your location when calling emergency services. For regular calls, the operator sees your IP address, which can be used to determine your approximate geolocation, but not your exact address.
Frequently Asked Questions (FAQ)
Does making calls over WiFi use up internet traffic?
Your mobile operator's data plan's gigabytes are not consumed. However, the internet service provider's data plan, which is connected to the router, is used. Typically, one minute of talk time consumes approximately 0.5–1 MB of data, which is negligible for modern unlimited home internet plans.
Is it possible to make calls via WiFi if the SIM card is not detected?
No, for VoWiFi to work, the SIM card must be active and readable by the phone. It is used for authentication on the operator's network. If you remove the SIM card, WiFi calling will not work, unlike with messaging apps, which are linked to your account.
Why is the WiFi icon on my phone lit up, but I can't make calls?
This may mean the service isn't activated on your carrier's end, or your phone hasn't registered with the IMS network. Try turning airplane mode on and off. If that doesn't help, check whether your specific data plan supports this feature.
Does VoWiFi work when the mobile network is turned off?
Yes, this is one of the main advantages. You can completely turn off mobile data or even put your phone in airplane mode (leaving only WiFi on), and calls will still go through. This is ideal for saving battery life and eliminating background connections to cell towers.