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

What is Wi-Fi calling?

Wi-Fi calling is a handy feature that lets you make voice calls and send text messages over the internet instead of cellular networks. It uses your phone number and works anywhere you have a Wi-Fi connection, letting you reach people even when mobile coverage is spotty.

Popular apps like WhatsApp and FaceTime have let people call over the internet for years using VoIP technology.* Wi-Fi calling is built on the same idea, but with a key difference — instead of running through a separate app, it’s handled by your mobile carrier. It uses your existing phone number and blends right into your phone’s built-in calling app. This way, you can reach anyone on any number, no extra app required on either end.

Wi-Fi calling is an especially useful feature abroad if you want to avoid roaming charges when calling or messaging people back home. This is because the call uses your Wi-Fi connection instead of a foreign cellular network, and your carrier bills it like a regular call from home. For every other online need, an eSIM can do the heavy lifting. For example, the Saily eSIM app works alongside your regular SIM card, so you can keep your number for Wi-Fi calling on your carrier’s plan and use Saily’s mobile data for everything else, without having to hunt for a Wi-Fi network.

*For more information on VoIP, read our “What is a VoIP phone?” article.

How does Wi-Fi calling work?

Wi-Fi calling can be compared to sending a voice message in real time. When you speak, your phone converts your voice into tiny digital data packets, sends them over the internet, and reassembles them into audio on the other end.

Wi-Fi calling can work in two ways:

1. Carrier-based Wi-Fi calling works through your mobile provider’s network. Once you turn the functionality on, your phone will automatically switch between cellular towers and Wi-Fi depending on which signal is stronger.

2. App-based Wi-Fi calling uses internet calling services that operate independently from your carrier. Apps like Skype, WhatsApp, or Zoom build their own calling networks, so they only need a solid internet connection.

Each method has its perks. Carrier-based Wi-Fi calling blends into your phone’s regular calling system, while app-based options may offer cheaper international rates and extra features. Take a look at the table below for a more detailed comparison of carrier-based and app-based Wi-Fi calling:

What is the difference between Wi-Fi calling and regular calling? 

Wi-Fi calling and regular calling will get your voice or text message to the other person in two entirely different ways. Regular calls travel through cellular towers — those tall antennas you’ve seen scattered across the landscape. Your phone connects to the nearest tower, which then routes your call through the mobile network to reach the person you’re calling.

Instead of the towers, Wi-Fi calling uses your internet connection. From your perspective, both feel the same. You dial the same way, use your phone’s regular calling app, and the person you’re calling sees your usual number. The only difference you might notice is a slight change in call quality, depending on how strong your internet is.

Take a quick look at this table to see the main differences between regular and Wi-Fi calling:

Benefits of Wi-Fi calling 

Wi-Fi calling allows you to stay in touch even when cellular signals are weak. It has solved many headaches for travelers and remote workers — and will likely solve some for you, too. Have a quick look at why it’s worth using:

• 

  Works even when cellular signal is weak. Whenever cellular connection drops, a nearby Wi-Fi network can pick up from there and carry through your phone calls and messages.

• 

  Can reduce costs of calling home from abroad. With Wi-Fi calling, calls back to your home country travel over Wi-Fi instead of a foreign cell network, and your carrier doesn’t apply additional roaming fees.

• 

  Uses your existing phone number. Your friends can call and text you the way they always do — using your original phone number.

• 

  Works without using additional apps. Wi-Fi calling lives right inside your phone's built-in dialer — just enable it in your settings and you're good to go.

Downsides of Wi-Fi calling 

Wi-Fi calling is a handy tool, but it has its quirks. Before you rely on it for staying in touch, you should consider the following aspects:

• 

  Call quality depends on internet speed and stability. If your Wi-Fi connection is slow or keeps dropping, your calls can be delayed or cut off mid-sentence.

• 

   Wi-Fi networks can be less secure than cellular networks. Open hotspots in cafés or airports may expose your phone to fake networks or data snooping — online threats a private mobile network usually shields you from.

• 

  Not all devices support Wi-Fi calling. Some older phones and smaller mobile providers can’t enable Wi-Fi calling. It’s worth checking your device compatibility before you count on this function.

• 

  Wi-Fi calling may drain your phone battery more quickly. Wi-Fi calling makes your phone juggle Wi-Fi and cellular connections in the background, which eats through the battery faster than a standard call would.

How much does Wi-Fi calling cost?

You don’t need to pay extra for Wi-Fi calling — it’s typically included in your mobile plan at no additional cost. Calls are billed the same way they’d normally be, so if you have unlimited minutes, those minutes stay unlimited whether your call goes over cellular or Wi-Fi. Charges only start to climb if you’re making international calls, and even then, the rates are usually the same as your carrier’s regular international calling fees, which can range from about US$0.50 to a few dollars per minute depending on the country.

If you’re using app-based services like WhatsApp, FaceTime, or Skype, calls between users are typically free. Meanwhile, calls to regular phone numbers abroad are often much cheaper than carrier rates — sometimes just a few cents per minute.

The only hidden cost to consider is data usage. Wi-Fi calling uses a small amount of data (usually less than 1 MB per minute for audio), so it won’t affect you if you’re on Wi-Fi, but it can add up if you use mobile data instead. 

How to enable Wi-Fi calling 

Wi-Fi calling is a lifesaver in low-signal areas where cellular towers can’t handle the connection. The best part is that the person you’re calling doesn’t need to be connected to Wi-Fi, and they don’t have to have Wi-Fi calling turned on. To set it up on your end, you have to make sure your device and mobile plan support the feature, then enable Wi-Fi calling in your settings and connect to a Wi-Fi network.

Enable Wi-Fi calling on an iPhone

These steps will turn on local carrier Wi-Fi calling on your iPhone:

1. Open the "Settings" app.

2. Go to "Apps," then tap "Phone" and select "Wi-Fi Calling."

3. Toggle on "Wi-Fi Calling on This iPhone."

4. Read and accept any terms or emergency address prompts from your carrier.

Once it’s on, your phone will automatically use Wi-Fi for calls whenever your cellular signal is weak.

Enable Wi-Fi calling on Android devices

Here’s how to enable local carrier Wi-Fi calling on Android devices (exact labels may vary by model):

1. Open “Settings.”

2. Go to “Connections” or “Network and Internet.”

3. Select “Mobile Network” or “SIMs”, then tap “Wi-Fi Calling.”

4. Toggle it on and follow any on-screen prompts from your carrier.

Your phone will now switch between Wi-Fi and cellular networks based on which has the stronger signal.

Enable Wi-Fi calling on VoIP apps

If your carrier doesn’t support Wi-Fi calling, or you prefer an alternative, you can use VoIP apps like WhatsApp, FaceTime, or Zoom. These work entirely over the internet and don’t rely on your mobile provider.

1. Download your chosen app from the "App Store" or "Google Play."

2. Create an account and give the app permission to use your microphone and contacts.

3. Connect to a Wi-Fi network.

4. Start a call directly through the app interface.

These apps are handy for international calls because most offer free or very low-cost rates when calling other users on the same platform.

Should Wi-Fi calling be turned on or off?

In general, it’s worth keeping the Wi-Fi calling function on because it will route your calls through a Wi-Fi connection whenever your cellular service is weak. Some scenarios in which you’ll benefit from Wi-Fi calling the most are:

• You’re somewhere with a weak cellular signal but strong Wi-Fi. Thick-walled offices, rural homes, and crowded venues can all weaken your cellular connection. But if there’s a nearby Wi-Fi network you trust, your phone has a clear path to stay online.

• You’re traveling abroad and want to call home. Wi-Fi calling sends the call over the internet instead of a foreign cell network, so your carrier bills it as a regular call from home without additional roaming charges.

• You rely on your phone for work. Having Wi-Fi calling on as a backup means you can stay in touch even when your cellular connection becomes weak.

However, in some situations, Wi-Fi calling can impair your connection instead of helping it. Learn about the times when it’s worth having Wi-Fi calling turned off:

• You’re on a slow or unstable Wi-Fi network. Patchy hotel or café Wi-Fi can make your calls choppy or drop them mid-sentence.

• You’re connected to an unsecured network. Open hotspots in airports or cafés come with security risks. It’s generally safer to switch to cellular for calls and texts in this instance.

• You need to call emergency services. Wi-Fi calling can sometimes route emergency calls to the wrong location, so cellular is generally the more reliable choice in emergencies.

Common Wi-Fi calling issues and how to fix them 

Wi-Fi calling is easy to set up, but like any tech feature, it can sometimes experience glitches. Here are a few common issues you might run into — and how to fix them:

• The Wi-Fi calling option isn’t showing up. Make sure your phone and mobile plan actually support Wi-Fi calling. On an iPhone, check “Settings” > “Phone” > “Wi-Fi Calling.” On Android, go to “Settings” > “Connections” or “Network and Internet” > “Wi-Fi Calling.” If you don’t see it, contact your carrier to confirm support.

• Wi-Fi calling is enabled, but calls still use cellular. This often happens when your cellular signal is stronger than Wi-Fi. Try putting your phone in airplane mode, then manually turn the Wi-Fi back on. It will force the device to use Wi-Fi for calls.

• Poor call quality or dropped calls. Wi-Fi calling depends on your internet connection. If your calls sound choppy or keep dropping, move closer to your router, switch to a faster Wi-Fi network, or restart your router to refresh the signal.

• Calls are not going through at all. Restart your phone to clear any temporary glitches. Also, double-check that data roaming is turned on if you’re traveling, as some carriers require it for Wi-Fi calling to work abroad.

• Emergency location info is missing. Some carriers require you to add an emergency address before you can make Wi-Fi calls. If prompted, follow the on-screen instructions to register your current address — it only takes a minute.

Tips for effective Wi-Fi calling

A few minor tweaks can make a big difference in how well Wi-Fi calling works. Keep these simple tips in mind for a smoother experience:

• Stick to a strong, stable Wi-Fi connection. The clearer your connection, the clearer your call. Stay close to your router and avoid networks that drop out frequently.

• Prioritize private networks over public ones. Public Wi-Fi in cafes or airports can be slow and crowded. Whenever possible, use home, hotel, or office networks for better reliability.

• Keep your phone’s software up to date. Regular updates often include improvements for network performance and Wi-Fi calling features, so don’t skip them.

• Enable Wi-Fi calling before you need it. Turn the feature on in your phone settings ahead of time so it’s ready to go when your cellular signal disappears.

• Switch to airplane mode if the cellular signal interferes. If your phone keeps defaulting to a weak mobile network, enable airplane mode and then turn Wi-Fi back on to force Wi-Fi calling.

Wi-Fi calling: Key takeaways

Wi-Fi calling is a simple way to stay connected when cellular coverage drops — or when you want to cut down on roaming costs. It routes your calls through the internet instead of cell towers, which can save money and make the connection more reliable in low-signal areas.

Like any technology, Wi-Fi calling has its trade-offs. It works best with a stable, high-speed connection, and call quality can suffer on crowded or slow networks. Still, for most travelers and anyone who often deals with spotty service, it’s a handy backup that can make staying in touch far less stressful.

Think of Wi-Fi calling as one more tool in your travel toolkit: easy to set up, reliable when you need it, and ready to keep your conversations going no matter where your adventures take you.