Wi-Fi Calling: How It Works, Why It's Needed, and How to Set It Up on Your Phone

Have you ever noticed that in areas with poor mobile network coverage, your phone suddenly prompts you to make a call via Wi-Fi? Or have you seen a mysterious "Wi-Fi Calling" switch in your smartphone settings? This technology has been actively implemented by telecom operators for several years now, but many users still don't understand how it works or why it's even necessary. Meanwhile, Wi-Fi calling They can be a lifesaver in situations where there is no cellular service but there is internet access—for example, in basements, remote villages, or abroad.

In this article we will figure out what it is Wi-Fi Calling (the official name of the technology), how is it different from VoIP (for example, WhatsApp or Skype), which operators in Russia and around the world support this function, and how to set it up correctly on iPhone And AndroidWe'll also cover the pitfalls: why calls sometimes drop, how this affects battery life, and whether you can make calls over Wi-Fi without a SIM card. If you often travel to places with unreliable signal or travel abroad, this information will save you time and money.

What is Wi-Fi calling and how does it work?

Technology Wi-Fi Calling (or Voice over Wi-Fi, VoWiFi) allows you to make voice calls and send SMS messages over the internet, rather than through traditional cellular networks. Your phone number remains the same, and the person you're calling sees a regular incoming call—as if you were calling over GSM. This is the main difference from messaging apps like Viber or Telegram: There is no need to install additional applications, register, or ask your interlocutor to also use the same service.

How does it work technically? When you make a call over Wi-Fi, your smartphone connects to the nearest access point, and the operator reroutes the voice traffic over the IP network (the internet) rather than through base stations. This is accomplished using special protocols—most often IMS (IP Multimedia Subsystem) or ePDG (Evolved Packet Data Gateway). It is important that Wi-Fi calls are encrypted at the operator level, making them more difficult to eavesdrop on than regular VoIP calls made via instant messaging apps..

• 📡 Don't confuse with VoIP! Calls via WhatsApp or Zoom — is VoIP (voice over IP), and Wi-Fi Calling is an extension of the mobile network.
• 🔄 Automatic switch: Modern smartphones automatically choose whether to make calls via Wi-Fi or the network, depending on the signal strength.
• 🌍 Works abroad: You can call a Russian number via local Wi-Fi, avoiding roaming charges.

The key advantage of the technology is seamless transition between Wi-Fi and the cellular network. For example, if you start a call at home via Wi-Fi and then go outside where there's a 4G signal, the call won't be interrupted. Carriers call this handover (call transfer). However, not all networks support this feature—it all depends on the provider and phone model.

Differences between Wi-Fi Calling, VoIP, and Messengers

Many people are confused Wi-Fi calling with voice calls in messengers. In fact, these are two different technologies with different operating principles. The main difference is Wi-Fi Calling integrated into the operator's mobile network, while VoIP (for example, in Skype or Discord) works through third-party services. Let's break down the key differences in the table:

Another important difference is connection qualityWi-Fi calls often sound clearer than VoIP calls because carriers use a codec HD Voice (For example, AMR-WB or EVS). In messengers, the quality depends on the compression algorithms of a specific application. For example, in WhatsApp the voice may sound "metallic", and in Wi-Fi Calling — as in a regular telephone conversation.

However, VoIP has its advantages: for example, you can make calls on a computer or tablet, and communicate with any messenger user, even if they don't have a SIM card. Wi-Fi Calling It is linked to your number and only works on your phone (with rare exceptions, for example, on some models) Samsung with function Call & Text on Other Devices).

Which operators in Russia will support Wi-Fi Calling in 2026?

At the beginning of 2026 Wi-Fi calling All major Russian operators officially support it, but with some caveats. It's important to understand that the technology only works if:

• 📱 Yours telephone compatible with the function (list below).
• 🌐 Yours router does not block protocols IMS or UDP 500/4500.
• 📡 The operator has activated the service for your tariff (sometimes connection is required).

Here are the updated materials on operators (data is subject to change - check in your personal account):

Important: Even if the operator supports the technology, Wi-Fi calling may not work in some regions or on certain tariffs. For example, Tele2 limits the function for corporate clients, and Beeline sometimes requires sending a USSD request *110*181# to activate.

⚠️ Attention: If you are using a virtual operator (eg. SberMobile or Tinkoff Mobile), please check with their support team about Wi-Fi Calling support. These operators often lease networks from the "big four," but not all features are transferred to end users.

Which phones support Wi-Fi calling?

Function Wi-Fi Calling It is available on most modern smartphones, but there are some important nuances:

• 🍎 iPhone: Supported since iPhone 6 (2014) on iOS 10 and later. The setting is hidden in the menu Settings → Phone → Wi-Fi Calling.
• 🤖 Android: Requires Android 9 (Pie) and above. Samsung the function can be called Wi-Fi calling, on Xiaomi — VoWiFi.
• ❌ Old models: Phones produced before 2018 (for example, Samsung Galaxy S7 or Huawei P10) may not support the function even after updating.

Here is a list of popular models with confirmed support (as of 2026):

To check if your phone supports Wi-Fi Calling, follow these steps:

⚠️ Attention: On some phones (eg. Realme or Oppo) The function may be hidden in the engineering menu. In this case, activating it may lead to malfunctions. It's best not to risk it unless your carrier confirms support.

How to set up Wi-Fi calling on iPhone and Android

The setup process varies depending on your operating system and phone model. Below are step-by-step instructions for iOS And Android.

Setting up on iPhone

1. Open Settings → Phone.

2. Tap on the item Wi-Fi calling (if it is not there, your operator does not support the function).

3. Switch the slider to the "On" position for your SIM card.

4. In the window that appears, select On for confirmation.

5. Wait for activation (this may take up to 5 minutes). Done! A message will appear next to the operator's name in the status bar. Wi-Fi.

Setting up on Android

The interface may differ, but the general scheme is as follows:

1. Go to Settings → Wireless & networks → SIM cards & mobile networks (or Settings → Connections → Mobile networks on Samsung).

2. Select your SIM card.

3. Find the item Wi-Fi calling or VoWiFi and turn it on.

4. If necessary, confirm activation (a reboot may be required).

On some phones (eg. Xiaomi) the path will be different: Settings → SIM cards & mobile networks → Advanced → Wi-Fi calling.

If the function does not work after enabling:

• 🔄 Restart your phone.
• 📶 Make sure you are connected to Wi-Fi (not mobile data).
• 📞 Check if your router is blocking protocols IMS (port 500/UDP).
• 📱 Update your phone firmware to the latest version.

What should I do if my carrier doesn't support Wi-Fi Calling?

If your carrier doesn't offer Wi-Fi Calling but you need internet calling, use alternatives:

- Install a messenger with VoIP (WhatsApp, Telegram, Viber).

- Activate the "Internet Calls" service with your operator (for example, for MTS it's "MTS Connect").

- Buy a SIM card from a virtual operator that supports VoLTE/VoWiFi (for example, SberMobile network-based Tele2).

Problems and Solutions: Why Wi-Fi Calling Isn't Working

Even if you have set everything up correctly, Wi-Fi calling may not work or break. Here are the most common problems and how to solve them:

One of the most common problems is Calls drop when switching between Wi-Fi and cellular networksThis happens if the operator does not support smooth handover. Solution:

1. Turn off mobile data during a call.
2. Use only Wi-Fi or only network (do not mix).
3. Update your phone's firmware (sometimes bugs are fixed in new versions).

Another common complaint is poor sound qualityThis may be due to:

• 📶 Overloaded Wi-Fi network (many devices connected to one router).
• 🔊 Operator codecs (some people use the outdated one AMR-NB instead of EVS).
• 🛑 Traffic blocking (for example, in corporate networks or hotels).

⚠️ Attention: If you use VPN on the phone, Wi-Fi Calling may not work. Disable your VPN or add a protocol exception. IMS in the VPN application settings.

Pros and cons of Wi-Fi calling: is it worth using?

Like any technology, Wi-Fi Calling has its advantages and disadvantages. We'll examine them in detail so you can decide if it's right for you.

Advantages

• 📶 Communication where there is no network: You can call from a basement, an elevator, or a remote village, if there is Wi-Fi.
• 💰 Savings in roaming: Calls are charged as domestic calls, even if you are abroad (if your operator supports it).
• 🔄 Smooth transition: The call is not interrupted when leaving the Wi-Fi coverage area (if the operator supports it) handover).
• 🔒 Safety: Carrier-level encryption is more secure than that of most messengers.
• 📱 No need for apps: Works through a standard phone number.

Flaws

• 🔋 Battery consumption: Maintaining a constant connection to Wi-Fi and your operator's network increases power consumption.
• 📵 Router dependency: If Wi-Fi goes down, the call may be disconnected.
• 🛑 Operator restrictions: Not all tariffs and regions support this function.
• 📡 Roaming issues: In some countries, Wi-Fi calling may be blocked by local laws.
• 🔊 Sound quality: Poor Wi-Fi may cause lag or interference.

So is it worth using? Wi-Fi Calling? Definitely yes, if:

• You often find yourself in places with poor mobile network signal.
• Are you traveling abroad and want to save on roaming charges?
• Your operator and phone support the function without any additional settings.

You should not enable this feature if:

• You have weak or unstable Wi-Fi.
• The operator charges an additional fee for calls over Wi-Fi (rare, but it happens).
• You are using a phone with a weak battery (the battery will drain faster).

FAQ: Frequently asked questions about Wi-Fi calling

❓ Is it possible to make calls over Wi-Fi without a SIM card?

No, for Wi-Fi Calling An active SIM card from a carrier that supports the technology is required. If you need calls without a SIM card, use instant messaging apps like WhatsApp or Skype.

❓ Why can't the other person hear me when I'm calling over Wi-Fi?

This may be due to:

• Poor Wi-Fi quality (check your internet speed).
• By blocking the microphone in the phone settings.
• Problems on the operator's side (restart the phone).

Try switching to a cellular network or using a different messenger.

❓ Does Wi-Fi Calling work on tablets?

Officially, no, since tablets do not have a SIM card slot (with rare exceptions, for example, Samsung Galaxy Tab S with eSIM support). However, some operators (for example, MTS) allow you to make calls from your tablet via the app MTS Connect, but this is no longer Wi-Fi Calling, and VoIP.

❓ Can I use Wi-Fi Calling to call short numbers (112, 911)?

Yes, but with some caveats. In most countries (including Russia), emergency calls are made via Wi-Fi. allowed, But:

• Your carrier must support this feature (check with your provider).
• In some areas, the call may be redirected to the local emergency number (for example, 112 instead of 911).
• It is best to use a cellular network for emergency calls, as it allows you to pinpoint your location more accurately.

❓ How do I disable Wi-Fi calling?

To deactivate the feature:

• On iPhone: Settings → Phone → Wi-Fi Calling → turn off the slider.
• On Android: Settings → SIM cards → Wi-Fi calling → disable the function.

Once disabled, the phone will only use the cellular network for calls.