Looking for ways to stay connected? With O2, WiFi Calling means you can make calls when you don't have signal. Meanwhile, 4G Calling offers better indoor coverage and clearer calls using our 4G network. But how do you know if your device is supported? What do you need to do to enable WiFi or 4G Calling? And where can you use it? Our guide has the answers.
What is WiFi and 4G Calling?
WiFi Calling (also called Voice over WiFi or VoWiFi) lets you call and text* as normal when you can't connect to a mobile network. All you need is a WiFi connection and you're able to stay in touch. Meanwhile, 4G Calling (also called Voice over LTE or VoLTE) means you can use our fast 4G network to make clearer voice call.
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.
*Text messaging over WiFi Calling is only supported on select devices.
Is my device supported?
All 4G and 5G devices that we stock will support 4G and WiFi Calling.
You should, however, check that your device is running O2 firmware. This is the software that makes your handset turn on and off – and, sometimes, there will be different versions for the same device. WiFi and 4G Calling only work on Android devices using O2 firmware.
How do I enable 4G and Wifi Calling on my device?
First, you'll need to add Wifi and 4G Calling to your account. It's quick and easy to do too.
For personal customers, please sign into My O2 and go to Device Details. From there, tap Wifi and 4G Calling – this is where you'll be able to add these features to your account.
Business customers will need to contact Business customer services, your Digital Advisor or Business Partner.
Once you add Wifi and 4G Calling to your account, you need to configure your device.
1. To enable WiFi Calling, go to Settings > Phone > Wi-Fi Calling. Make sure WiFi Calling is set to On. To switch off WiFi Calling, set the toggle to Off.
2. To switch on 4G Calling, go to Settings > Mobile Data > Mobile Data Options > Enable 4G and then Voice & Data to enable 4G Calling. To switch off 4G Calling, select ‘Data’.
If you don't see a Wifi 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 setup process may restart your device –but you can receive these instructions by email. For more information, please see our iPhone support guides.
Watch how to set up Wifi and 4G Calling on a iPhone on YouTube.
1. To enable Wifi Calling, go to Settings > Connections > WiFi calling. Make sure Wifi Calling is set to On. To switch off Wifi Calling, set the toggle to Off. If you can’t find the settings here, try going to Phone > tap the 3 dots in the top right corner > Settings > scroll down to find Wifi Calling and toggle On.
2. To switch on 4G Calling, go to Settings > Connections > Mobile networks > 4G Calling. Make sure 4G Calling is set 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 software:
• 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.
Please note: This setup process may restart your device but you can get these instructions by email. Our Samsung help guides contain more information too.
Watch how to set up Wifi and 4G Calling on a Samsung on YouTube.
If you are using a J3 (2017) to get WiFi and 4G Calling, your device will need to use O2 firmware. This is essentially the software that makes your device turn on and run. Sometimes there are different versions of firmware for the same device.
Your device should use O2 firmware if you bought it direct from us in an O2 shop, online or over the phone.
To check if your phone’s running O2 firmware, dial *#1234# and look at the CSC entry. If this line includes ‘TEF’, ‘O2U’ or ‘OTF’ then your device has O2 firmware and you can set up WiFi and 4G Calling.
If the CSC doesn't include one of these codes then WiFi and 4G Calling isn’t supported on your phone right now. Pop into an O2 store to discuss your options.
To enable WiFi Calling, go to Settings > More > WiFi calling. Make sure WiFi calling is set to On. To switch off Wifi Calling, set the toggle to Off.
To switch on 4G Calling, go to Settings > More > Mobile networks > Enable VoLTE. Make sure WiFi calling is set to On. To switch off 4G Calling, set the toggle to Off.
For more help, check out our Sony phone help guides.
If you are using a Sony XZ Premium, XZ1 or XZ1 Compact, to get Wifi and 4G Calling, your device will need to use O2 firmware. This is essentially the software that makes your device turn on and run. Sometimes there are different versions of firmware for the same device. Your device should use O2 firmware if you bought it direct from us in an O2 shop, online or over the phone.
To check if your Sony is running O2 firmware:
Open the ‘Chrome’ app and tap the Home icon in the top left corner. If this takes you to www.o2.co.uk then your device has O2 firmware. If it takes you to Google, then WiFi and 4G Calling isn’t supported on your phone right now.
If you have changed the homepage in Chrome since buying your device, tap the three dots in the top right corner of Chrome, tap Settings, tap homepage, tap to edit the homepage and then press ‘Reset’. If it resets to www.o2.co.uk, then your device has O2 firmware. If it resets to Google, then WiFi and 4G Calling isn’t supported on your phone right now.
If that's the case, pop into an O2 store to discuss your options.
Go to Settings > SIM & network > Enhanced communications. Make sure WiFi calling is set to On. To switch off WiFi Calling, set the toggle to Off.
Go to Settings > SIM & network > Enhanced communications. Make sure Enable VoLTE (4G Calling) is set to On. To switch off 4G Calling, set the toggle to Off.
Need more help? Check out our OnePlus device support guides.
Go to Settings > SIM & network > Enhanced communications. Make sure WiFi calling is set to On. To switch off WiFi Calling, set the toggle to Off.
Go to Settings > SIM & network > Enhanced communications. Make sure Enable VoLTE (4G Calling) is set to On. To switch off 4G Calling, set the toggle to Off.
Need more help? Check out our OnePlus device support guides.
Go to Settings > Call > tap on WiFi Calling to turn on. To switch off WiFi Calling, tap to remove the tick.
Go to Settings > Call > tap on 4G Calling to turn on. To switch off 4G Calling, tap to remove the tick.
WiFi and 4G Calling FAQs
Got WiFi coverage – but can’t connect to the mobile network? Your phone will automatically use WiFi Calling.
iPhone
The carrier message at the top of your screen will change to ‘O2 WiFiCall’. If you have a strong phone signal, your phone will automatically use 4G Calling and your bearer will show as ‘4G’.
Android
The indicator bar will display a WiFi/phone icon. If you're in a 4G Calling area with good coverage, your phone will automatically use 4G Calling and your bearer will show as '4G'.
Calls made over WiFi will only drop if you move out of range and 4G Calling isn't activated or available. If you’re in an area where both WiFi and 4G Calling are available, the call will use 4G first.
You can check 4G Calling coverage using our coverage checker.
You can use WiFi Calling wherever there is WiFi – including wherever O2 WiFi is available. It’s free to connect to O2 WiFi, but remember other providers might charge you to connect – like on certain trains and in some hotels.
It’s no different to making a standard call or sending a standard text message (if you have a supported device that allows for SMS services over WiFi). It will come out of your tariff allowances 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.
Yes you can. WiFi and 4G Calling is currently available on most O2-compatible devices.
Transferring your personal tariff to a SIM only contract and want to add WiFi and 4G Calling? Add it to your account at no extra charge in My O2.
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.
WiFi and 4G Calling isn’t available on Pay As You Go at the moment. It’s available to Pay Monthly Consumer and Business customers with compatible devices and services.
WiFi Calling is not currently supported outside of the UK. In certain circumstances, however, it may be possible to enable WiFi Calling when abroad. Where used, additional charges will apply.
Mobile calls will use 2G/3G Roaming and you’ll be charged according to your normal tariff.
If you're on a personal tariff, you can use O2 Travel to stay connected when you’re abroad.
If you're on a business tariff, you can use our Rest of the World 24 Hour Pass to stay connected while you’re away.
Yes – but it's not available on the O2 Business Mobex, Best for Business tariffs or Public Service Network tariffs.
WiFi and 4G Calling won’t work with some of our other services – including O2 Just Call Me, Mobex, Mobile Recording or Fax and Data. You’ll need to remove WiFi and 4G Calling to use them. This can be done through My O2 or your Business Advisor.
If you're on a personal tariff, sign in to My O2, select ‘Device details’, then ‘WiFi and 4G Calling’. From here, follow the instructions to either add/remove Wifi and 4G Calling from your account.
If you're on a business tariff get in touch with your Digital Advisor, Business Partner, or Business customer services if you need help with WiFi and 4G Calling
Sending voicemails and texts when using WiFi Calling without mobile coverage:
SMS (text messages) can be sent and received over WiFi Calling but only on certain devices where the device firmware allows. Some devices will not be able to send and receive text messages over WiFi Calling.
MMS and Visual Voicemail (VVM) messages need mobile coverage to reach your phone so these won’t work in WiFi-only areas.
iPhone customers – iMessage will continue to work even if you only have WiFi coverage available.
You can still use WiFi Calling to make calls to the emergency services. Please note – if you dial 999 using WiFi Calling where there’s no mobile coverage, the operator will need to ask where you’re calling from. This is because WiFi calls don’t show location information.
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.
