Wi-Fi calling (VoWiFI) is a handy feature for people who struggle with weak cellular network signals, but it’s often misunderstood. In this guide, we debunk the most common myths and explain how the technology really works.

What Is Wi-Fi Calling?

It is a smartphone feature that lets you make calls over wifi and send texts when your cellular network signal is weak. Your phone uses this functionality to route the calls through a wireless internet network (Wi-Fi).

During a call, the voice data is sent over the Wi-Fi network instead of your cellular network. The other person receives it as a normal phone call.

Common Misconceptions About Wi-Fi Calling

It is a very useful feature, but many users have incorrect assumptions about how it operates. Let’s clarify the most common misconceptions:

Infographic showing the top common misconceptions about Wi-Fi calling

1. Wi-Fi Calling Works Without Cellular Network and a SIM

Many people believe that the service works without a SIM or eSIM or cellular network. However, this is not the case, as it can't work if your phone is not registered to your network carrier.

For this service to work, your phone must initially register your SIM for authentication with your cellular network provider. If the authentication is not achieved, then Wi-Fi calling can't work.

This is simply a voice data routing service that uses a wireless internet network, rather than being a standalone calling service. It can't replace your phone's ability to make a voice call; rather, it works as a support for your voice calls when cellular network reception is poor.

2. Wi-Fi Calling Is the Same as Internet Calling Apps

It is not like a WhatsApp or Skype call, which solely use the internet for making voice and video calls.

Services like WhatsApp, Facebook, and Skype calling do not require your SIM, phone number, or cellular network to work. These services will even work when there's no cellular network on your phone, or it is in flight mode.

On the other hand, Wi-Fi calling requires SIM authentication, your carrier's telecom infrastructure, and your phone's ability to support it.

Every smartphone can be able to make a WhatsApp or Skype call, but the same can't be said for this feature, as it requires dedicated support within the phone's software.

3. Is Wi-Fi calling on your phone free?

Wi-Fi calling is not free, and any calls that you make (local, national, or international) get charged as per your subscription plan. Using this feature doesn't have any effect on your monthly rental.

So, if you think that you can make free international calls with Wi-Fi, you may end up with unexpected charges in your monthly phone bill. Treat this feature as a support to your weak cellular network instead of expecting free usage.

However, there's a significant benefit for travelers who go abroad. If you're placing a Wi-Fi call from abroad to your home country, most network providers may treat it as a local call; this may prevent roaming charges, but this is not 100% guaranteed.

A word of advice is that you should always talk to your network provider before using the service abroad. Your network provider or the LBO (Local Breakout Operator) may use your IP address or GPS to charge you for roaming even during a Wi-Fi call.

Telecom companies are very good at tracking exactly how you use your phone, so use this feature carefully to avoid a surprise on your bill.

4. Any Wi-Fi Network Will Work Perfectly

Don’t assume this feature to work on every network you join. For a call to be clear, the connection needs more than just speed; it needs low latency. High "lag" or a crowded signal can make your voice sound robotic or cause the call to drop instantly.

Public or office networks often use firewalls that may block the specific UDP ports (like 500 or 4500) your carrier uses for IPsec tunnels. If these digital paths are closed, the service simply won't connect. Unlike a video that can buffer, a live call needs a perfectly stable, low-latency stream to stay active.

5. Faster Wi-Fi Guarantees Better Calls

While fast Wi-Fi speeds are great for streaming, speed isn't the only thing that matters for a phone call. Your network also needs to support specific routing protocols like IPsec and SIP. Think of these as the "secure tunnels" your voice travels through to reach your carrier.

In the absence of these protocols—which often happens on restrictive office or hotel networks—your phone won't be able to "handshake" with your provider. Even with blazing-fast internet, if a firewall blocks these specific paths, the feature will stay stubbornly disconnected.

It’s also about stability. Unlike a YouTube video that can buffer, a live conversation happens in real-time. If your connection has high "jitter" or brief interruptions, your call will drop instantly, no matter how many megabits you have.

6. Wi-Fi Calling Drains More Battery

With the advancements in smartphone technology, Wi-Fi itself is a low-powered tech. The latest standard, Wi-Fi 6E, WiFi 7 is even more power-efficient than its predecessors. This standard introduces the 6GHz band, which reduces congestion and allows the phone to complete data transfers faster, letting the radio go back to sleep sooner.

This is known as Target Wake Time (TWT), and it significantly boosts battery life. So, Wi-Fi calling actually saves your smartphone battery, as it doesn't have to constantly search for a network. Wi-Fi networks that run on a fixed fiber or copper line are highly stable and reliable.

Contrary to the Wi-Fi network, a weak cellular network drains more battery than these calls ever will. By using the more efficient standards and avoiding the strain of hunting for cell towers, your device stays charged much longer.

7. Wi-Fi Calling Guarantees Indoor Coverage

The feature depends on the strength and placement of your Wi-Fi router. Poor indoor Wi-Fi leads to dropped or low-quality calls despite enabling the functionality.

8. Wi-Fi Calling Works During Carrier Outages

Your phone's network may see an outage anytime due to weather, natural calamities or non-working cell towers. In such a case you can't expect the service to work for you because there would be no cellular network for initial authentication.

However, in such a situation if your Wi-Fi network works then you can simply place a WhatsApp, Facebook or Microsoft Teams call.

9. Wi-Fi Calling Is Only Useful When Signal Is Weak

It is always helpful whenever you face call drops due to weak cellular network reception. However, it is also beneficial for international roaming, basements, indoors, and whenever you prefer battery efficiency.

10. Emergency Calls Always Work With Wi-Fi Calling

When you call 911 through a cell tower, the system uses nearby towers and GPS to find you. However, this is different. Since your voice travels over the internet, the network only knows you’re online—not where you’re standing.

To fix this, carriers use E911 (Enhanced 911). You must register a "home base" address so dispatchers know where to send help if you can't speak. If you travel and forget to update this, responders could end up at your old address. In an emergency, that simple update is a lifesaver.

11. Wi-Fi Calling Replaces Signal Boosters

Cellular network signal boosters work by extending the range of your network to areas where the signal struggles to reach. However, Wi-Fi calling doesn't extend your network; instead, it is a call routing feature that uses the internet.

There's no direct comparison between signal boosters and this service. Also, it can't fully replace signal boosters. You may have several phones at your home, and only some of them might be compatible with the feature. The remaining phones are still reliant on the signal booster for indoor coverage.

12. Wi-Fi Calling Can Work In Flight Mode

Flight mode disrupts all cellular network services. However, Wi-Fi can still work with flight mode enabled. But Wi-Fi calling will never work when flight mode is enabled.

As Airplane mode disables cellular services, your SIM loses network connection; as a result, the feature can't let you place a call. This happens because, when flight mode is enabled, the initial SIM authentication can never be achieved.

For the call to route, the phone needs to verify the IMSI (International Mobile Subscriber Identity) from your SIM card. If the Android system interprets "Flight Mode" as a total hardware cutoff for the SIM tray, that authentication bridge is broken.

Essentially, the "handshake" between your SIM and the carrier is severed at the source. Even if your internet is active, the call won't route because the device can no longer prove your identity to the network.

I tried this myself on an Android smartphone with flight mode enabled, Wi-Fi did work but Wi-Fi calling didn't in my country.

How to Get the Most Out of Wi-Fi Calling

  • Ensure your Wi-Fi network is stable, low-latency, and properly configured.
  • Keep your phone software and carrier settings up to date.
  • Verify that your E911 address is registered with your carrier.
  • Use the service in conjunction with strong indoor Wi-Fi placement or mesh systems.
  • Understand your plan: this feature does not eliminate charges for local, national and international calls.

FAQ — Frequently Asked Questions

Q1. Do I Get Charged For Wi-Fi Calling?

Yes, but Wi-Fi calling is not separately chargeable on your monthly phone bill. You use this service only to route your voice calls via internet. All calls made through Wi-Fi network are still chargeable as per your subscription plan. Your network carrier charges you for making calls and sending text but not for the Wi-Fi usage.

Q2. Do All Phones Have WiFi Calling?

No, all phones do not support this feature. This feature is more common on latest smartphones and several dated phones but is not available on every phone out there.

Q3. Does Wi-Fi Calling Avoid Roaming Charges?

No, it can't avoid roaming charges. Using Wi-Fi calling abroad is still chargeable as an international roaming call by your LBO (Local Breakout Operator) or the international roaming partner.

Q4. How Can I Tell If My Phone Is Using Wi-Fi Calling?

Check your phone's status bar where it shows you network signal and battery icons. If your phone is using WI-Fi calling at any moment then you may see 'WiFi1' for SIM1 and 'WiFi2' for SIM2. You may also see VoWiFi or a Wi-Fi icon placed over a telephone receiver just next to the network signal icon.

Final Thoughts

Wi-Fi calling is a powerful tool for improving connectivity, but it is not magic. By understanding the common misconceptions and using it correctly, you can enjoy clear calls indoors, during travel, and in weak signal areas. Remember that call quality depends on stable Wi-Fi, carrier support, and device capability. Avoid unrealistic expectations, and it will enhance your communication experience.