Wi-Fi Calling: Everything you need to know

Posted on 25th August 2017 under Blog.

Mobile phones have become an extension of who you are, they do so many tasks – it’s essential they work constantly.

And when they don’t, frustration sets in. Especially when it comes to attempting to make a phone call only to discover your network coverage is poor, or non-existent.

Have you been on a call only to lose service as soon as you step in through the doors of your office building? Or commuted on the train and repeatedly cut off while speaking to a client? The situation can be very annoying for both sides of the call.

Technology has come a long way though, and there’s a service which addresses all the issues related to bad network coverage – Wi-Fi calling.

What is Wi-Fi calling?

Indoor network coverage has always been a problem, even for the superfast 4G networks. The next generation mobile network, 5G, is set to solve the problem. But it’s still a few years before it gets rolled out around the country and becomes the new standard.

So, one way of avoiding bad reception is to allow for phone calls and texts to work over the internet. As bad network coverage is one of the main reasons customers switch to different operators, WI-FI calling has become a feature which helps retain and boost customer numbers.

The feature allows a mobile phone to use a WI-FI network and the internet to make phone calls and send and receive texts. That’s how people in poor signal areas, such as rural towns and the tube, can use their phones even if there’s zero network coverage.

Most WI-FI networks should be compatible with the service. That includes your home broadband, as well as coffee shops, airports, train stations and other locations with reliable Wi-Fi.

How’s this different to Skype, WhatsApp and other VoIP apps?

Although it’s true that all of the above services use the same VoIP (Voice Over IP) technology, with WI-FI calling there’s no disruption to the end-user. The mobile device switches back and forth between the mobile network and internet automatically when available.

All activity should be seamless, and there’s no need for installing separate apps. Messages and call logs are stored in the usual place, and the risk of missing text or calls is no bigger than when using 3G or 4G.

What’s the call quality of Wi-Fi calling?

Like with every internet-dependant service, the call quality will depend on the strength and quality of your Wi-Fi signal and internet connection. In general, you shouldn’t notice a difference when compared to making calls over 3G and 4G.

To avoid poor call quality and cut offs, most network providers recommend at least 1Mbps (UK national average in 2016 was 28.9Mbps) and strong signal to make Wi-Fi calls.

If you’re noticing consistently poor call quality, there might not be enough bandwidth for the network to handle your calls. This often happens when using busy public Wi-Fi networks or when streaming movies at home.

What are the downsides of WI-FI calling?

Although very useful, it has its shortcomings. Most network providers don’t offer Wi-Fi calling outside of the UK, so you won’t be able to benefit from it in poor signal areas abroad.

If you need to call the emergency services on 999, they won’t be able to triangulate your location which can help them find you easier.

And if your phone doesn’t support 4G, the switch between the traditional network and Wi-Fi probably won’t be seamless and may cut off. This means you’ll have to call again once you’ve switch to either 3G or Wi-Fi.

Which networks offer Wi-Fi calling?

Currently in the UK only three networks offer WI-FI calling:

To use WI-FI calling on their network, you need:

  • A Pay monthly Red Extra or Red Entertainment plan, a Red or Red Value Bundle, Red+, Business Value, Business Extra, Business Premier or Business Black
  • iPhone 7, iPhone 7 Plus, iPhone 6s, iPhone 6s Plus or iPhone SE
    Samsung Galaxy A3 (2016 and 2017), A5 (2016 and 2017), S6, S6 edge, S7, S7 edge, S8, S8+, XCover 4
  • Vodafone Smart ultra 7, Smart platinum 7


With them, WI-FI calling is available to:

  • Pay monthly and small business (not available on pay-as-you-go)
  • Corporate customers on 4GEE plan
  • iPhone 5c and later models of the iPhone
  • Samsung Galaxy S8, S8+, S7, S7 edge, A3 (2017), or A5 (2017)
  • Nexus 5X or Nexus 6P
  • Lumia 550, 650, 950 or 950XL
  • HTC 10 or HTC U11
  • BlackBerry Priv or BlackBerry Dtek 50
  • Google Pixel or Google Pixel XL
  • Huawei P10, P10 Lite or P10 Plus.


O2’s WI-FI calling feature is available to:

  • Pay Monthly, SIM Only or business contracts
  • iPhone 7, 7 Plus, 6S, 6S plus or SE
  • Samsung S7 or S7 Edge
  • Sony Xperia XZ Premium