Enabling Voice-Over-WiFi on the OnePlus 5T and Three UK

My mobile provider - Three UK - offers WiFi calling, but only if you have a phone purchased directly from them. For everyone else, they have a crappy app which hasn't been updated in two years.

So, let's break out of their artificial restrictions and get some WiFi calling on the OnePlus 5T!


  1. Open your phone dialler app.
  2. Dial *#800#
    Dialler screen.
  3. You don't need to press send, you should automatically be taken to this engineering menu
    Log Test menu screen.
  4. Touch the top menu item "oneplus Logkit"
  5. Scroll to the bottom
    Log Menu screen.
  6. Press "Function Switch"
  7. Select "VoWifi switch"
    VoWifi Switch.
  8. Your phone will ask to reboot - so press OK to reboot
  9. Once the phone has restarted, go to your Settings menu
    Android settings menu.
  10. Select "SIM & network"
  11. Scroll down and select "Wi-Fi calling"
    Use WiFi Calling switch.
  12. You can optionally switch the "Calling preference" to "Wi-Fi preferred". If you do that, calls will go via Wifi even if you have a mobile signal.

Test it!

Put your phone into Aeroplane mode, then switch on WiFi. You should see this logo at the top of your screen.

VoWifi Logo on the top of the Android display.

Try to make a call.

It doesn't work??!

If this doesn't work for you... sorry! You should speak to your network provider to see what they recommend.

One thought on “Enabling Voice-Over-WiFi on the OnePlus 5T and Three UK

  1. This is outstanding, and exactly what I was after. Thank you for putting this on your blog :o)



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