Help and Support

Wifi and 4G Calling

Wifi and 4G Calling

Want to know if your phone supports Wifi and 4G Calling? Not sure what it is or how it works? What about how to set it up? We’re here to help.

See how to set up Wifi and 4G Calling on your phone.

iPhone 7 set up

Samsung Galaxy S7 set up

Wifi and 4G Calling FAQs

iPhone 7 setup

How do I set up Wifi and 4G Calling - iPhone 7

First you will have to check that you currently do not have an incompatible service (e.g. TU Go).

1. To enable Wifi Calling, go to Settings > Phone > Wi-Fi Calling. Make sure Wi-Fi Calling is set to On.

2. To switch on 4G Calling, go to Settings > Mobile Data > Mobile Data Options > Enable 4G and then Voice & Data to enable 4G Calling.

If you don't see a Wi-Fi Calling or 4G Calling menu option, you may have to update to the latest iPhone software:

  • Go to Settings > General >Software Update. Install an update if available (you’ll need iOS 10.3 or above).
  • Once installed go to Settings > General > About. The ‘Carrier’ value on this screen should be set to 28.3 or above. If this hasn’t updated automatically, you should get a message from us to update to new carrier settings. Accept by pressing ‘Update’.
  • Follow the instructions above to enable Wifi and 4G Calling.
Please note: This set-up process may re-start your device so if you would like to receive these instructions by email please send us an email and we will send them over.

Samsung Galaxy S7 setup

How do I set up Wifi and 4G Calling - Samsung Galaxy S7

Samsung Galaxy S7 and S7 edge

1. To enable Wifi Calling, go to Settings >Phones > Wi-Fi calling. Make sure Wi-Fi calling is set to On. To switch off Wifi Calling, set the toggle to Off.

2. To switch on 4G Calling, go to Settings > Connections > Mobile networks > 4G calling. Make sure Wi-Fi calling is set to On. Set this to On. To switch off 4G Calling, set the toggle to Off..

If you don’t see a Wifi Calling or 4G Calling menu option,you may have to update to the latest Android firmware and add Wifi and 4G Calling to your account:

  • Go to Settings > Software update > Download updates manually.
  • If a new software update is available, select ‘Download now’. Once the download completes, your handset will prompt you to install a new version of the software. You can either select ‘Install update’ or schedule the update overnight.
  • When the install process starts, the device will display the Android installation status bar and then restart. Your screen will show the installation has completed. Select ‘OK’. You may need to wait for your device to optimise your existing apps for the new software.
  • For personal tariff customers – Sign in to My O2 to add Wifi and 4G Calling.
  • Business customers – Contact Business customer services, your Digital Advisor or Business Partner.
  • Once your new services are added to your account, follow the instructions above to enable Wifi and 4G Calling.

Please note: This set-up process may re-start your device but you can get these instructions by email.

To get Wifi and 4G Calling your Galaxy S7 or S7 edge will need to use O2 firmware*. It should do if you bought it direct from us in an O2 shop, online or over the phone. We’re working to make it available on other Galaxy S7 and S7 edge phones as soon as we can be sure the experience is great. We’ll get in touch when this happens.

To check if your phone’s running O2 firmware, dial *#1234# and look at the ‘CSC’ entry. If this doesn’t include ‘TEF in the text then we’re sorry, Wifi and 4G Calling isn’t supported on your phone right now. We’re working on it for later in the year and we’ll be in touch when it’s ready. If you need more info, contact us or O2 Business customer services.

*The device firmware is essentially the software that makes your device turn on and run. Sometimes there are different versions of firmware for the same device.

Wifi and 4G Calling FAQs

What is Wifi and 4G Calling?

Wifi Calling (also called Voice over Wifi or VoWifi), allows you to make and receive calls even if you can’t connect to the mobile network. When connected to wifi, you can just dial the number you want to call like normal.

4G Calling (also called Voice over LTE or VoLTE) lets you make calls using our fast 4G network, for a clearer voice call. If 4G Calling is available, you can just dial the number you want to call like normal. You can check 4G Calling coverage using our coverage checker.

They're two great ways to stay connected with O2. Wifi Calling can help when you can't get a signal, and both give you great quality calls. In 4G Calling areas, they work together to provide a seamless and uninterrupted experience as you move from one to another, without the call dropping.

What phone do I need?

From launch, Wifi and 4G Calling is available to iPhone 7, 7 Plus, Galaxy S7 and S7 edge customers on personal Pay Monthly, sim-only and business tariffs, with more devices coming very soon.

To get Wifi and 4G Calling your Galaxy S7 or S7 edge will need to use O2 firmware*. It should do if you bought it direct from us in an O2 shop, online or over the phone. We’re working to make it available on other Galaxy S7 and S7 edge phones as soon as we can be sure the experience is great.

To check your phone’s running O2 firmware, dial *#1234# and look at the ‘CSC’ entry. If this doesn’t include ‘TEF’ in the text then we’re sorry, Wifi and 4G Calling isn’t supported on your phone right now. We’re working on it for later in the year and we’ll be in touch when it’s ready. If you need more info, contact us or O2 Business customer services.

*The device firmware is essentially the software that makes your device turn on and run. Sometimes there are different versions of firmware for the same device.

How do I pay for Wifi and 4G Calling?

It’s no different to making a standard call now. It will come out of your call allowance or be charged at the standard tariff rate if you run out.

  • No extra charges from O2 – a minute is just a minute no matter how you make the call.
  • 4G calls will not cost you any data.
  • Wifi calls use very small amounts of data over your wifi connection.
  • If the wifi is unlimited or free (like O2 Wifi) then you won’t be charged anything extra. If your wifi connection has an allowance, then it will come out of that allowance, and your wifi provider may charge if you go over.
  • Multi-Party calls: These are charged as normal but please note that each identical part of a multi-party or conference call will appear on your bill as a separate call entry.
Can I use Wifi and 4G Calling on an O2 sim-only contract?

Yes you can.

  • Using an iPhone 7 or 7 Plus with your sim-only contract? To add Wifi and 4G Calling at no extra charge, either go to My O2 and add it to your account, or contact us.
  • Transferring your personal tariff to a sim-only contract and want to add Wifi and 4G Calling? Either go to My O2 to add it to your account at no extra charge, or contact us.
  • Have an O2 Business sim-only contract and want to add Wifi and 4G Calling? Get in touch with your Account Manager, Digital advisor, Business Partner or Business customer services to add it to your account at no extra charge.
Will my phone automatically use Wifi or 4G Calling?

When you have wifi coverage but can’t connect to the mobile network, your phone will automatically use Wifi Calling. The carrier message at the top of your screen will change to ‘O2 WifiCall’. Calls made over wifi will only drop if you move out of range and 4G Calling isn’t activated or available.

If you have a strong signal, your phone will automatically use 4G Calling and your bearer will show as ‘4G’. You can check 4G Calling coverage using our coverage checker.

If you’re in an area where both Wifi and 4G Calling are available, the call will use 4G first.

Where can I use Wifi Calling?

You can use Wifi Calling wherever there is wifi, including the London Underground where O2 Wifi is available. Go to London Underground for more information. It’s free to connect to O2 Wifi, but remember other wifi providers might charge you to connect, like on certain trains and in some hotels.

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

You can’t use Wifi and 4G Calling when you’re abroad. Wifi calls won’t work. Mobile calls will use 2G/3G Roaming and you’ll be charged according to your normal tariff.

Consumer customers – Use O2 Travel to stay connected when you’re abroad.
Business customers - Use O2 Travel for Europe or our Rest of the World 24 Hour Pass to stay connected while you’re away.

Can I use Wifi and 4G Calling on an O2 Business tariff?

Yes, but at launch Wifi and 4G Calling isn’t available on the O2 Business Mobex or the Best for Business tariffs.

Can I use other O2 services with Wifi and 4G Calling?

Consumer customers - sign in to My O2 to switch between TU Go and Wifi and 4G Calling.

Business customers - Contact Business customer services, your Digital Advisor or Business Partner if you need help with moving from TU Go to Wifi and 4G Calling.

Please note: Adding Wifi and 4G Calling will permanently delete your TU Go account and data, including any call and text history stored in TU Go.

Some business services are also currently incompatible, including O2 Just Call Me and Mobile Recording. For help with this, contact Business customer services.

Voicemail and texts when using Wifi Calling without mobile coverage

1. SMS, MMS and Visual Voicemail (VVM) messages need mobile coverage to reach your phone so these won’t work in wifi-only coverage areas.

2. You’ll still be able to receive voicemails but, as above, text notifications will only work if you have mobile coverage so you’ll need to dial 901 to check for new messages.

3. iMessage will continue to work even if you only have wifi coverage available.

Is there anything else I need to know?

You can still use Wifi Calling to make calls to the emergency services. Please note that if you dial 999 using Wifi Calling where there’s no mobile coverage, the operator will need to ask where you’re calling from as wifi calls don’t show location information.

Was this content helpful? Yes | No

Thank you for sending your feedback.

Topics from O2 Community

Can't find what you're looking for?

Give us a moment

We're just checking to see if there's an available agent.

Live Chat - Busy

All our agents are currently busy, please try again later.

Live Chat - Offline

The service is currently offline.