Many smartphone users are familiar with the experience of suddenly losing mobile service in a thick-walled building or in a remote area. At such times, the "No Service" or "Emergency Calls Only" icon appears on the screen, making it impossible to make important calls. However, modern technology allows you to bypass this limitation by using wireless internet for voice communication.
Technology Voice over Wi-Fi (VoWiFi) is integrated into most modern smartphones and supported by major carriers. This allows you to turn any available Wi-Fi router into a cellular hotspot, ensuring high-quality audio even in areas where a base station signal can't reach.
In this article, we'll detail how to activate this feature on various devices, the requirements for it to work, and how to avoid hidden costs. You'll learn the intricacies of setting it up. Android And iOS, and you'll also understand the difference between Wi-Fi calls and popular instant messaging apps.
How VoWiFi technology works
Technically, Wi-Fi calls involve transmitting voice traffic over IP protocols, similar to how information is transmitted when browsing the web. Your carrier uses special gateways that redirect your voice packet from the internet to their cellular network, preserving your regular phone number.
The main advantage VoWiFi The advantage of this method is its transparency for the user. You don't need to inform the other person you're in a poor reception area or ask them to install an additional app. For both the caller and the recipient, it looks like a regular call using a standard dialer app.
Connection quality directly depends on the stability of the internet connection and bandwidth. If the router is overloaded with multiple connected devices or the internet speed is low, voice quality may be interrupted, even though the connection is formally established.
⚠️ Attention: Wi-Fi calling doesn't automatically work when roaming in all countries. Before traveling, be sure to check with your carrier whether VoWiFi is supported in your country to avoid international roaming charges.
It's important to understand that when switching between networks (for example, leaving home with Wi-Fi coverage and going outside with mobile service), modern smartphones try to maintain the connection. However, in some cases, a call may be interrupted if switching between technologies VoLTE and VoWiFi did not work correctly.
Checking device and operator compatibility
Before you begin setting up the app, make sure your hardware and plan support the required functionality. Not all older smartphone models or budget plans support voice over the internet.
Telecom operators must have the technical capability to route such calls. In Russia and the CIS, the major market players (the "Big Four") have already implemented this service, but it may not be activated by default on older SIM cards.
- 📱 Smartphone: The device must support IMS (IP Multimedia Subsystem) technology. Almost all phones released after 2016 do.
- 📶 Operator: The service must be available in your region and activated on your number. Often, you'll need to replace your SIM card with a new one that supports 4G/5G.
- 🌐 Firmware: Your phone's operating system must be updated to the latest version, as software providers regularly add support for new operators.
There's a simple way to check for support: if a phone icon with a Wi-Fi symbol or the text "Wi-Fi Call" appears in the status bar after enabling the feature, everything is working correctly. The absence of the icon after enabling the setting may indicate a block from your carrier.
Sometimes smartphone manufacturers release firmware versions for a specific region that exclude support for certain carriers. In such cases, changing the device's region or installing the global software version may be necessary, which is a more complex procedure.
Setting up Wi-Fi calling on Android
In the operating system Android The activation process may vary slightly depending on the manufacturer's operating system (Samsung, Xiaomi, Realme, etc.), but the general steps remain the same. First, find the appropriate switch in the settings menu.
Typically the path to the setting looks like this: go to Settings → Connections → Mobile networkHere you should find the "Wi-Fi Calling" option. If you don't see it in this menu, try searching for "Wi-Fi" in your settings.
After activating the slider, the system may prompt you to select a network priority. We recommend setting "Wi-Fi Preference" so that the phone always tries to use a wireless network for calls when available, saving battery life and improving call quality indoors.
☑️ Activation checklist for Android
On some devices, for example, from the brand Xiaomi or HuaweiTo activate the function, you may need to enter a special code or activate a hidden menu through engineering settings, but this is rare for modern global firmware versions.
| Smartphone brand | Menu path (standard) | Peculiarities |
|---|---|---|
| Samsung | Settings → Connections → Wi-Fi Calling | Automatically detects the operator |
| Xiaomi / Redmi | Settings → SIM cards and mobile networks | May require an operator profile update. |
| Google Pixel | Settings → Network & Internet → Mobile network | Maximum native integration |
| Honor | Settings → Wireless & networks → Wi-Fi calling | Often hidden in advanced settings |
If the icon doesn't appear in the status bar after enabling the feature, try restarting your device. Sometimes the system needs to re-register with the operator's network to apply new configuration settings.
Instructions for iPhone (iOS) owners
Product users Apple Users will appreciate the ease of setup, as the iOS interface is unified. The feature is called "Wi-Fi Calling" and is located in the phone's standard settings menu. iOS 9 or later is required.
To activate, open Settings → Phone → Wi-Fi CallingToggle the switch to the on position. The system will ask you to confirm your address for emergency services, as geolocation is determined differently when calling over the internet than via cell towers.
A unique feature of the ecosystem Apple The ability to receive calls from your iPhone on other devices (iPad, Mac, Apple Watch) as long as they are connected to the same iCloud account and on the same Wi-Fi network. This allows you to never miss important calls, even if your phone is in another room.
⚠️ Attention: When you first enable this feature on your iPhone, you must confirm or enter your emergency services address (911/112). Your carrier will use this information when you call emergency services via Wi-Fi.
To the owners iPhone You should also pay attention to your cellular data settings. Make sure that in the menu Settings → Cellular There is no data transfer limit for system services, although VoWiFi voice traffic is usually not charged as Internet traffic.
What should I do if the Wi-Fi Call icon is missing on my iPhone?
If the icon disappeared after updating iOS, go to Settings → General → About. If a carrier settings update appears, accept it. This is a common cause of network settings resets.
Tariffs and traffic consumption
One of the most frequently asked questions concerns the cost of such calls. It's important to distinguish between "internet traffic" and "call minutes." When you call via VoWiFi, your carrier doesn't count it as using up your internet plan's megabytes.
Calls are charged against the minutes included in your plan, just like a regular cell phone call. If you have unlimited minutes, Wi-Fi calls are also free (within your country).
The situation changes if you're abroad. VoWiFi technology allows you to make calls "as if you were at home." This means if you're in Turkey but connected to Wi-Fi and call your operator's number in Russia, the call is charged as an incoming/outgoing call within your home network, rather than international roaming.
- 🏠 At home: Tariff minutes are used up, Internet traffic is not used up.
- ✈️ In roaming (incoming): Often free, as if you were at home (depending on the operator).
- 📞 In roaming (outgoing to local calls): It is charged as a call from the home network to the country of residence.
However, rules are subject to change. Some virtual mobile operators (MVNOs) may have their own restrictions. Always check the terms of your specific tariff plan in your personal account.
Solved problems and errors
Despite the technology's robustness, users may encounter difficulties. The most common issue is the inability to activate the feature or its sudden deactivation. This is often related to the SIM card profile.
If your SIM card has been in use for several years, it may not have the necessary applets for authorization in the operator's IMS network. In this case, the only solution is to replace the SIM card at a mobile phone store or through a courier, which is usually free.
Another cause is conflicting power saving settings. Aggressive power saving modes can disable Wi-Fi in the background when the phone's screen is off, resulting in connection drops or the inability to answer incoming calls.
Actions in case of failures:1. Restart your smartphone.
2. Toggle Airplane Mode on and off.
3. Delete the Wi-Fi network profile and reconnect.
4. Reset network settings (Settings → System → Reset).
It's also worth checking whether your router is blocking certain ports or protocols required for SIP signaling. This is rare on home routers, but on corporate networks or public Wi-Fi (cafes, airports), such calls are often blocked by firewalls.
Why can calls over Wi-Fi be of worse quality than over the network?
Quality depends on ping (latency) and jitter (latency instability). Cellular networks prioritize voice, while home Wi-Fi can be overloaded with torrents or 4K video, causing voice packets to get stuck in the queue.
Is it possible to make calls via Wi-Fi if there is no SIM card in the phone?
VoWiFi technology requires an active SIM card for initial authentication with the operator's network. Without a SIM card, the phone will not be able to register with the IMS domain and establish a voice call connection.
Does VoWiFi affect internet speed?
Voice traffic takes up very little space (approximately 64-128 kbps). However, if the channel is bottlenecked, the router may prioritize voice packets, which may cause page loading to slow down slightly.
Does this feature work if the router is sharing the Internet from a mobile phone (modem mode)?
Yes, it works. The operator doesn't care how your phone accesses the internet. The important thing is that the IP address is assigned and the connection to the VoWiFi gateways is established.
Do you need an operator app for calls?
No, VoWiFi technology doesn't require apps; it's a system feature. Operator apps (like "My MTS" or "MegaFon") are only used to manage your plan, not to make Wi-Fi calls.