Wi-Fi Calling — technically Voice over Wi-Fi (VoWiFi) — lets your phone route normal voice calls and SMS through a Wi-Fi network instead of the mobile network. The other person dials your normal number — they don't know or care that you're on Wi-Fi.
When it helps
- Basement, thick walls, rural homes: no cellular signal but Wi-Fi works
- Travel: hotel Wi-Fi lets you receive UK calls abroad without roaming charges
- Underground / metro stations: where free Wi-Fi exists
How to enable
Settings → Phone → Wi-Fi Calling (iOS) or Settings → Connections → Wi-Fi Calling (Samsung). Toggle on.
Compatibility
Supported on all four UK networks. Most modern phones (iPhone 6+, Galaxy S6+) support it. Some MVNOs disable it — check before relying on it.