What is Wi-Fi calling and should I turn it on?

Poor mobile signal indoors is usually a building problem rather than a network problem — thick stone, foil-backed insulation, modern coated glass and steel frames all block the radio frequencies mobile networks use. No amount of complaining to the network fixes a house that blocks radio. Wi-Fi calling sidesteps the problem by not using radio to the mast at all.

Safety

Step by step

1. Find it in the mobile or calls section of settings.It is usually within the mobile network or SIM settings, sometimes under calls, and on dual SIM phones it is a per-line setting you may need to enable on each. It is a phone setting rather than an app, and it appears only if your network supports it — all the major UK networks do.
2. Register an address when it asks.You will be asked for an address for emergency calls. Give the address you will most often use it at, and update it if you move. This is a legal requirement rather than a marketing form, and it is the one part of the setup that genuinely matters.
3. Check the status indicator.When it is active, the status bar usually shows a wi-fi calling label or a small icon alongside the signal indicator. If it never appears, check the setting is on, that you are on wi-fi, and that the router is not blocking it — some business and public networks do.
4. Test it deliberately.Put the phone in aeroplane mode, turn wi-fi back on, and make a call. If it connects, wi-fi calling is working, because there is no mobile radio at all in that state. This is a far better test than making a call in a room with marginal signal.
5. Understand what does not change.Your number, your allowance, your billing, and the fact that it is a mobile call in every respect the network cares about. Calls come out of your minutes; they are not free-because-internet, and they are not cheaper when calling abroad unless your network says so.
6. Understand what does change.Call quality now depends on your broadband. A congested or unstable connection produces stuttering that sounds like a phone fault. A broadband outage takes calls with it unless the phone can fall back to the mast. And you become reachable in places you were not before, which is mostly good and occasionally not.
7. Know about the handover.Walking out of the house mid-call hands over from wi-fi to the mast. Some networks do this seamlessly; others drop the call. Test it once so you know which yours does, and end important calls before leaving the house if it drops.
8. Consider the alternatives if it is not supported.If your network or phone does not support it, a signal booster from the network, a femtocell, or simply using a calling app over wi-fi are the options. Never buy a third-party mobile repeater — operating one without the network's permission is an offence in the UK.

Tips

• Wi-Fi calling also fixes texts. A two-factor code that never arrives at home is one of the most irritating symptoms of poor indoor signal, and this solves it.
• It works on any wi-fi, not just at home — a hotel, an office, a holiday cottage. Abroad, it usually routes as if you were in the UK, which can make calls home free, but check your network's terms because they vary.
• If both partners in a household have poor signal on different networks, both should turn this on. It is per-phone and per-line.
• On a dual SIM phone, enable it separately on each line. It is easy to turn it on for the personal line and wonder why work calls still drop.

Questions people ask