Many users face a situation where there's no cellular service in a room, but wireless internet is available. In offices with thick concrete walls, basements, or country houses with poor coverage, this becomes a real problem, as missing an important call is highly undesirable. It's precisely for such situations that carriers and smartphone manufacturers have implemented technology. Voice over Wi-Fi, which allows you to make voice calls over an Internet connection, bypassing standard base stations.
Technology VoWiFi Voice over Wi-Fi (Voice over Wi-Fi) works by transmitting voice over IP protocols, similar to how popular messaging apps work, but integration occurs at the system level. This means you don't need to open a separate app or ask your contact to install the same app—you simply dial a number in your standard dialer, and your phone automatically routes the signal over an available Wi-Fi network. The sound quality is often higher than that of a regular call, thanks to support for high-definition codecs.
The introduction of this feature has been a revolutionary step in improving coverage in buildings where installing additional cell towers is not cost-effective. Now, any router with access to the global network can become a mini base station for your smartphone. In this article, we'll cover in detail how to activate this feature on various devices, the nuances that different carriers have, and what to do if the feature isn't working correctly.
How VoWiFi technology works and its advantages
The technology is based on the protocol IMS (IP Multimedia Subsystem), which enables the transmission of multimedia content, including voice, over packet networks. When you dial a number, your smartphone detects that the cellular signal is weak or absent, but Wi-Fi is active. The device encrypts the voice stream and sends it to the operator's server, which routes the call to the public telephone network or another subscriber. The entire process occurs almost instantly and is seamless to the user.
The main advantage is the ability to stay connected in "dead coverage" zones. If you're in a building with shielding materials or in a remote area where only 2G coverage is available, having wireless internet is a lifesaver. Furthermore, audio quality When using HD Voice over Wi-Fi, it often outperforms standard GSM calls, making speech more natural and intelligible even in noisy environments.
Another important aspect is battery conservation. In extremely weak cellular signal conditions, the smartphone switches to enhanced search mode, which leads to rapid battery drain. Switching to Wi-Fi for calls reduces the load on the radio module. It's also worth noting that during a call via VoWiFi The mobile internet speed does not drop as a separate communication channel is used.
⚠️ Attention: VoWiFi technology requires support from your carrier. Even if your phone supports it, you won't be able to activate it without the appropriate plan or service from your carrier. Check the terms and conditions in your personal account.
Checking device and operator compatibility
Before you begin setting up your device, you need to make sure your equipment and SIM card are ready to work with modern communication protocols. Not all smartphone models released several years ago have built-in support. VoWiFiIn addition, telecom operators create "whitelists" of devices that have passed testing and are guaranteed to operate reliably.
Typically, this technology is supported by all flagship models released after 2018, as well as many mid-range devices. If you have a custom firmware or a device intended for a different market (for example, a Chinese version of a global brand), the feature may be hidden in software. In such cases, you may need to reflash the firmware or activate it through the engineering menu, which is not recommended for those without experience.
The list of major operators in Russia supporting this technology is constantly growing. The largest market players have long since implemented this option for their subscribers. However,
Below is a table showing the support status of the technology among the main operators (status may change, it is recommended to check for relevance):
| Operator | Android support | iOS support | Need for connection |
|---|---|---|---|
| MTS | Yes (most models) | Yes | Automatically / Personal account |
| Megaphone | Yes | Yes | Calls via Wi-Fi service |
| Beeline | Yes | Yes | Automatically if VoLTE is available |
| Tele2 | Yes | Yes | Automatically |
⚠️ Attention: Operators' personal account interfaces and service names may change. If you don't find an option in the usual location, use the app search or contact support chat.
How to enable Wi-Fi calling on iPhone
For smartphone owners Apple Luckily, we're lucky to have a unified settings interface. To activate this feature, your device must be running the latest version of the operating system. iOSThe setup process is extremely simple and takes just a few seconds. First, make sure the Wi-Fi module is enabled and connected to the network.
Go to your device's main settings, scroll down, and select "Phone." In the list that appears, find "Wi-Fi Calling." Toggle the slider to on. The system may ask you to confirm your address for emergency services, as calling over the internet determines your location differently than calling via cell towers. Once enabled, the "Wi-Fi" icon will appear in the status bar next to your carrier's name.
If the standard route doesn't work, try the alternative route via the cellular menu. Follow the path Settings → Cellular, select your SIM card (if you have more than one), and find the "Wi-Fi Calling" toggle. In some cases, you may need to restart your device for the changes to take effect.
☑️ Check iPhone settings
It is important to note that on iPhone the function only works if the service is activated. VoLTE (Voice over LTE). Carriers often bundle these two technologies, so make sure "LTE, VoLTE mode enabled" is enabled in your cellular network settings.
Setting up the feature on Android smartphones
In the ecosystem Android The situation is a bit more complicated due to the variety of shells from different manufacturers. The path to the settings may have different names, but the logic remains the same. Most often, the option is located in the SIM card settings section or in the general network settings. On devices Samsung you need to go to Settings → Connections → Wi-Fi Calling.
On smartphones Xiaomi And Redmi the path usually looks like this: Settings → SIM cards and mobile networks → (Select SIM card) → Use Wi-Fi for callsIf you don't see this option, your model may not be certified by your carrier, and activation will require entering a special code or changing the region in your phone settings, which is a more complex procedure.
For devices Google Pixel and other smartphones with pure Android, the menu is located at Settings → Network & Internet → Mobile Network → Wi-Fi CallingAfter enabling, it is recommended to select an operating mode. The available options are: "Prefer mobile network," "Prefer Wi-Fi," or "Do not use." To save data when roaming, it is best to select "Prefer Wi-Fi."
⚠️ Attention: On some Android models, the settings menu may be hidden. If you're sure your carrier supports it but the option isn't in the menu, try entering the code. ##4636## in the dialer (does not work on all devices) and check the phone information settings.
VoWiFi billing and roaming
One of the most frequently asked questions concerns the cost of such calls. It's crucial to understand: a call over Wi-Fi is charged exactly like a regular voice call according to your plan. Minutes are consumed from the bundles included in the plan. If you have unlimited calls to numbers in your region, they will also be free over Wi-Fi.
The roaming situation here is most interesting and advantageous for travelers. If you're abroad and connected to Wi-Fi (at a hotel or cafe), incoming and outgoing calls are often charged as calls from your home network, meaning no international surcharge. This allows for significant savings, as you're effectively "virtually" in your home country.
However, there are some nuances. Some operators may consider Wi-Fi calls while roaming a separate service or apply special conditions. For example, a call to a number in the host country may be considered international, while a call to a number in your home region may be considered local. Always check the terms of your plan before traveling.
What happens if the internet connection runs out during a Wi-Fi call?
If the Wi-Fi connection is lost, a modern smartphone will attempt to seamlessly switch the call to the cellular network (handover), but this is only possible with VoLTE support and coverage. Without VoLTE, the call will simply be dropped.
It's also worth keeping data usage in mind. A voice call consumes relatively little data—approximately 1-2 MB per minute, depending on the codec quality. However, if you're using public Wi-Fi, be careful.
Possible problems and solutions
Despite the technology's maturity, users may encounter difficulties. The most common issue is that the Wi-Fi icon doesn't appear in the status bar, even though the settings are enabled. First, check whether the service is activated with your carrier. Often, you'll need to send a USSD request or confirm the connection via SMS.
The second common issue is unstable connection quality or interruptions. This may be due to a congested Wi-Fi channel or a weak router signal. VoWiFi Sensitive to latency (ping). If your wireless network is slow, voice quality will drop sharply. In this case, rebooting the router or switching your smartphone to the 5 GHz frequency, if supported, will help.
Another problem is the inability to identify the emergency number. As mentioned earlier, when calling over the internet, the operator may not see your exact geolocation. In emergency situations (112, 102, 103), always try to use a regular cellular network, even if the signal is weak, or clearly state your address to the dispatcher.
In rare cases, resetting network settings can help. This will delete saved Wi-Fi passwords and Bluetooth settings, but it often resolves software conflicts with communication modules. Path to reset: Settings → System → Reset → Reset network settings.
Frequently Asked Questions (FAQ)
Do I have to pay for Wi-Fi calls if I have an unlimited plan?
No, there are no additional charges. The minutes from your basic plan are used. If you have an unlimited plan, calls remain free. Internet traffic consumption is minimal and usually unnoticeable compared to your overall usage.
Is it possible to make calls via Wi-Fi if the SIM card is blocked or there is no signal at all?
Yes, that's the primary purpose of this technology. If the SIM card is active and the service is connected, but there's no cellular signal (or it's blocked by airplane mode with Wi-Fi enabled), you can still make calls. The key is an active internet connection.
Why is there no Wi-Fi Calling option on my Android?
Your smartphone is likely not whitelisted by your carrier, or its firmware isn't certified to work with IMS profiles in your region. Try updating your phone's software or contact your carrier's support team for an activation code.
Does using VoWiFi affect mobile internet speed?
No, it doesn't. Calls are made over Wi-Fi, so your mobile data (3G/4G/5G) remains free. You can talk and download files simultaneously over the mobile network if Wi-Fi suddenly goes down, but the call itself will be interrupted.
Does this feature work in international roaming?
Yes, it does. Moreover, it's often the most cost-effective way to communicate abroad. Incoming and outgoing calls over Wi-Fi while roaming are often charged at the same rate as within your home network, but be sure to check the terms of your specific data plan before traveling.