Modern smartphones have long since ceased to be simply a means of voice communication, but the quality of cellular coverage is far from always ideal. Owners Android-devices often encounter situations where the signal in a room is lost, and incoming calls become unavailable. This is where technology comes to the rescue. VoWiFi (Voice over Wi-Fi), which allows you to make calls over a wireless network even when there is no cell tower signal.
Enabling this feature can significantly improve connection quality in offices, country houses, and basements. However, the activation process isn't always straightforward, as smartphone manufacturers hide settings in various menu sections. Furthermore, the service requires support from your mobile operator and proper device configuration.
In this article, we'll detail how to set up Wi-Fi calling on various smartphone models, what conditions must be met, and what to do if the option doesn't appear in the menu. You'll learn how to check plan compatibility and avoid common activation errors.
VoWiFi Technology: How It Works and Why It's Necessary
Technology VoWiFi Allows voice calls to be transmitted over an internet connection, using the wireless network infrastructure instead of the base station's radio signal. This process is completely transparent for the user: you dial the number as usual, and the phone automatically switches the voice transmission channel. This is especially useful in buildings with thick walls or in remote areas where the LTE/4G signal is weak or absent.
The main advantage is that the sound quality is often higher than with a regular cellular connection, and data consumption is minimal. Carriers typically don't charge for this data separately, but consider it part of the bundled minutes. It's important to understand that VoWiFi is not the same as making calls via instant messengers., because it uses your real phone number and the caller doesn't need to install any additional apps.
For the technology to work reliably, a stable internet connection with a ping of no more than 100 ms is required. If the network is congested or has low bandwidth, connection quality may deteriorate, and the phone will automatically switch back to the cellular network if coverage allows. In some cases, if the Wi-Fi signal is weak, the device may lose the connection, so a stable router is critical.
⚠️ Please note: VoWiFi functionality depends on your router settings. If you have strict packet filtering or SIP port blocking enabled, calls may not go through. On corporate networks, VoWiFi access may be restricted by the administrator.
Checking operator and tariff plan compatibility
Before you look for settings on your phone, you need to make sure that your mobile operator supports the technology. Voice over Wi-FiIn Russia, the major market players (the "Big Four") have already implemented this feature, but the terms and conditions may vary. The service is often free, but requires subscription or activation in the subscriber's account.
Not all tariff plans support this option by default. Some older, archived tariffs may require upgrading to the latest line. It's also important that the SIM card be up-to-date, although in most cases, simply re-signing the network profile is sufficient, either at a mobile store or through the operator's app.
Activating the service often requires sending a USSD command or using a mobile app. Without an active service from your operator, the phone's menu may be hidden or inactive, even if the smartphone itself technically supports the technology.
A universal way to enable it through Android settings
Most modern smartphones are powered by Android 10 and above are configured through the standard menu. The interface may differ slightly depending on the operating system version and the manufacturer's shell, but the logic remains the same. You'll need to find the section responsible for SIM cards and mobile networks.
The sequence of actions usually looks like this:
- 📱 Open "Settings" and go to "Connections" or "Network & Internet".
- 📶 Select "Mobile network" or "SIM cards".
- 🔌 Find the "Wi-Fi Calling" switch and turn it on.
- ✅ Confirm the action if prompted for permission.
Once enabled, a corresponding icon should appear in the status bar (at the top of the screen), often designated as Wi-Fi Call or a phone icon with a Wi-Fi symbol. If the switch is missing, try updating your network settings or checking for system updates.
Setting up VoWiFi on Samsung smartphones
Devices Samsung One UI apps have their own customization algorithm, which can be hidden in the quick settings menu. Users often search for this option in the deep settings, forgetting to check the top notification shade. To start, pull down the notification shade twice to reveal all the buttons.
If the "Wi-Fi Calling" button isn't visible in the shortcuts, tap the three dots in the upper-right corner of the panel and select "Edit." Find the desired button in the list of available ones and drag it to the active panel. Tapping the icon will enable the feature, and an indicator will appear in the status bar. VoWiFi.
For more fine-tuning, go to Settings → Connections → Wi-Fi CallingHere you can select your network priority. For example, you can configure your phone to prefer the mobile network even if Wi-Fi is available, or vice versa. This is useful if your wireless network is unstable.
Hidden codes for Samsung diagnostics
Enter the code ##4636## in the phone app to access the testing menu. There you can check the IMS status and VoWiFi registration, but be careful about changing settings without understanding the process.
Activating the feature on Xiaomi, Redmi, and POCO
Smartphones XiaomiMIUI and HyperOS-based devices often require an additional step to activate hidden features. There may be no standard switch if the SIM card wasn't automatically recognized as supporting VoWiFi. In this case, activating it through the engineering menu helps.
To access advanced settings, enter the dialer code ##869434##If the message "VoWiFi Carrier check was disabled" appears after entering the code, carrier verification is disabled, and the feature should work. If the message says "enabled," carrier verification is enabled, and the phone may be blocking the feature due to a carrier and settings mismatch.
It's also worth checking your access point (APN) settings. Sometimes entering the correct APN for your carrier solves the problem. Go to Settings → SIM cards and mobile networks → Access point names (APNs) and make sure the correct profile is selected. In some cases, creating a new access point with the operator's default settings helps.
| Model / Series | Setting location | Peculiarities |
|---|---|---|
| Xiaomi Mi / Note | Settings → SIM cards | Activation via code is often required |
| Redmi Note | Settings → Connections | Depends on the MIUI version |
| POCO F / X | Settings → Mobile network | A stable 5 GHz Wi-Fi connection is required. |
| Black Shark | Game Center / Settings | May be blocked in game mode |
Troubleshooting: Why VoWiFi Isn't Working
Even if all conditions are met, the function may not work. One common cause is using a router with outdated firmware or incorrect security settings. Encryption protocols WPA2/WPA3 must be supported correctly. If the router only distributes the network in the 2.4 GHz band with high load, call quality will be poor.
Another issue is an IP address or DNS conflict. Try changing your DNS to a public one, such as Google's, in your phone's Wi-Fi settings.8.8.8.8) or Cloudflare (1.1.1.1). This often helps if your ISP blocks ports needed for VoIP traffic.
It's also worth checking if your phone is in "Data Saver" or "Ultra Data Saver" mode. These features can block background data transfers, which are necessary for your phone to connect to your carrier's Wi-Fi network. Disable them to test.
☑️ Diagnosing VoWiFi issues
⚠️ Please note: Emergency services (112, 102, etc.) may not work when making calls over Wi-Fi while roaming or without geolocation. Your carrier may not see your exact address because your internet provider uses dynamic IP addresses.
Frequently Asked Questions (FAQ)
Is there an extra charge for Wi-Fi calls?
No, operators charge these calls according to your plan, just like regular minutes. Internet traffic is also not consumed from your main plan; it's used as a separate, free channel.
Does VoWiFi work in international roaming?
Yes, this is one of the best ways to save money while roaming. While abroad, you connect to local Wi-Fi and call Russian numbers as if they were your home numbers, using the rates of your home region, avoiding incoming and outgoing roaming charges.
Why does the VoWiFi icon appear and disappear?
This indicates an unstable Wi-Fi signal. The phone constantly switches between the cellular network and Wi-Fi. To resolve this, try moving closer to the router or switching to the 5 GHz frequency, which is less noisy.
Is it possible to use VoWiFi without a SIM card?
No, the technology requires an active SIM card from a carrier that supports the service. The SIM card itself may not have a network connection (for example, in a basement), but it must be inserted into the phone to authenticate to the carrier's network via the internet.