WiFi and 4G Calling Explained

Two more ways to stay connected with O2

Make calls when you don’t have signal with WiFi Calling. Get clearer calls and better indoor coverage with 4G calling. Both features are available at no extra charge with O2.

Find out more

Wifi and 4G Calling

Take advantage of more great ways to see what you can do with O2 WiFi Calling and 4G Calling. No signal? No problem. WiFi Calling lets you make calls over a WiFi connection – whether you're at home or on the go. Meanwhile, O2 4G Calling uses our 4G network for much clearer calls.

You'll move seamlessly between WiFi and 4G network coverage to continue your call if you're using WiFi or 4G Calling. You can still check your social media or send an email while you're on the phone too. 

All 4G and 5G devices we stock now support 4G and WiFi Calling. On some Android devices, these features will only work if you're using our firmware. This is essentially the software that makes your device turn on and run. There are sometimes different versions of firmware for the same device too.

Use our device help guides to find out more about setting up WiFi or 4G Calling on your phone.

The best of wifi and 4G

WiFi symbol with people using different types of devices devices

How WiFi and 4G Calling works

  • Start your call using your office WiFi network and then, as you step outside, seamlessly move onto our 4G network – if it's available. Check your 4G coverage.

  • You'll be good to go once we set you up and you switch the feature(s) on. There's no need to sign up, register or download an app. 


Use our device guides to set up WiFi and 4G Calling.


Businessman holding mobile phone in front of office building

No extra charges

  • Calling/messaging over WiFi or 4G is no different to making a standard call or sending a standard text message*. It comes out of your monthly tariff allowances – or be charged at the normal tariff rate.
  • There are no extra charges. A miniute is just a minute, howeer you make a call. And you won't use any data to make a 4G call. Wi
  • If your WiFi connection is free or unlimited, there'll be nothing extra to pay. If your WiFi connection has an allowance, however, your call will come out of that.
  • If your device supports SMS services over WiFi.
Young woman holding mobile phone on London underground

More places to connect

  • You can make calls, take calls and send/receive text messages* wherever you have a WiFi connection. So, you'll be able to stay in touch in more places than ever.
  • You'll still be able to use te internet or apps on our 4G network while you're making a call.
  • If your device supports SMS services over WiFi
Wifi and 4G calling icon

Using Wifi and 4G Calling

WiFi and 4G Calling won't work with some of our other services – such as O2 Just Call Me, Mobex or Mobile Recording. You'll need to remove them to use WiFi and 4G Calling. If you change your mind later though, don't worry – you can just switch back through My O2 or via your Business Advisor.


Terms apply

More about Wifi and 4G Calling

Coverage and connectivity

Check your network coverage

See what O2 network coverage is like where you are.

More about O2 Wifi

Take advantage of free O2 WiFi when you're out and about.

More about 4G

With 4G from O2, get the things you love in an instant.

Help and support

Get your questions answered on WiFi and 4G Calling.


How do I set up Wifi Calling?

Our device guides contains all the information you need to set up WiFi Calling on your handset.


How do I set up 4G Calling?

Use the right device guide for you to learn how to set up 4G Calling on your phone.

How do I pay for Wifi and 4G Calling?

Using either WiFi or 4G to stay connected costs the same as a standard call or text message*. So, that means it'll come out of your tariff allowances in the normal way. Or you'll be charged at the standard tariff rate if you run out.

*If you have a supported device that allows for SMS services over WiFi.



Where can I use Wifi Calling?

You can use it wherever there's a WiFi connection you can use – including anywhere O2 WiFi is available.

Can I use Wifi and 4G Calling to make calls abroad?

No. We don't currently support WiFi Calling outside the UK. In certain circumstances, however, it may be possible to enable the feature when abroad. If so, additional charges will apply.