1. SentryFi
2. WiFi guides
3. Is Wi-Fi Calling safe?

How a Wi-Fi call is carried

With Wi-Fi Calling on, your phone connects over the internet to a gateway run by your mobile carrier (in the standards it is called the ePDG). 3GPP’s security specification TS 33.402 sets out how the phone and that gateway establish security: an IPsec tunnel negotiated with IKEv2, authenticated with your SIM. Your call and texts then travel inside that tunnel to the carrier’s network, the same as a call over the cell network.

• Other people on the hotspot can see that your phone is talking to your carrier, but not the call itself.
• The WiFi owner can see the same connection and how much data it uses; the tunnel stays encrypted to them too.
• Your carrier handles the call exactly as it would on cellular.

Turn it on: iPhone

1. Open Settings > Cellular > Wi-Fi Calling. If you have more than one SIM, choose the line first.
2. Turn on Wi-Fi Calling on This iPhone.
3. Enter or confirm your address for emergency services if your carrier asks for it.

If the option isn’t there, your carrier or plan may not support it.

Turn it on: Android

1. Open Settings > Network & internet > SIMs.
2. Tap your carrier’s SIM, then turn on Wi-Fi calling.
3. If you don’t see the option, Google says your carrier doesn’t support it. Some steps only work on Android 6.0 and up, and menus vary by phone maker.

Google also notes you may be charged for calls over WiFi, depending on your carrier.

Emergency calls

Apple’s page is specific: when cellular service is available, your iPhone uses it for emergency calls. If you turn on Wi-Fi Calling and cellular isn’t available, emergency calls might use Wi-Fi Calling, and your device’s location may be used to help responders. That is why carriers ask for an emergency address when you set it up: keep it current, especially if you travel.

When Wi-Fi Calling is a weaker choice

• Your carrier’s implementation. A 2024 study by the CISPA Helmholtz Center found 13 of 275 operators using flawed keys for the IPsec setup, affecting an estimated 140 million customers. You can’t check this yourself; keep your phone updated, as fixes may arrive through carrier settings.
• A WiFi sign-in page you haven’t finished. Until you complete a hotel or airport captive portal, the tunnel can’t be built and calls fail or fall back to cellular.
• Networks that block it. Some office and public networks block the ports the tunnel needs. The call then falls back to cellular or fails; it doesn’t go out unencrypted.
• A lookalike network. The tunnel keeps the call private, but a fake network can still show a fake sign-in page. Don’t type passwords or card details into it.

Is it safer than a cellular call?

Neither is end-to-end encrypted like a call in a secure messaging app: in both cases your carrier carries the call. Wi-Fi Calling mainly adds a tunnel across the WiFi part of the path. For sensitive conversations, an app with end-to-end encryption is the stronger choice on any connection. The FTC’s general advice for public WiFi still holds: rely on encrypted apps and don’t ignore warnings. SentryFi doesn’t change phone or router settings. It checks the network you are on for warning signs — an unexpected sign-in page, DNS answers that differ from trusted DNS, certificate problems, a hidden proxy — and gives a 0–100 risk score with plain next steps.