Unlock Your iPhone With Your Apple Watch: Setup and Limits

Your Apple Watch can unlock your iPhone when Face ID cannot see your face — but only then. Something has to be covering you, and the watch has to be on your wrist, unlocked and nearby. That one condition is why most people conclude the feature is broken: with a bare face, Face ID simply works, and the watch is never asked.

What you need

• An iPhone with Face ID (iPhone X or later) on iOS 14.5 or later.
• An Apple Watch Series 3 or later on watchOS 7.4 or later, paired to that iPhone.
• Wi-Fi and Bluetooth switched on for both — you do not have to be joined to a network.
• A passcode on the watch, and wrist detection turned on.

How do I turn it on?

1. On the iPhone, open Settings > Face ID & Passcode and enter your passcode.
2. Scroll to Unlock with Apple Watch and switch on your watch's name.

If wrist detection is off you will be asked to turn it on first. The feature depends on it: without wrist detection the watch cannot tell whether it is still on you or sitting on a desk beside your phone.

Why isn't it unlocking?

1. Is your face actually covered? A mask over your mouth and nose, or sunglasses or goggles over your eyes. An uncovered face hands the job back to Face ID.
2. Is the watch unlocked and on your wrist? If you took it off it locked, and it will not authorise anything until you enter its passcode.
3. Is Bluetooth on for both devices? Check in Settings rather than Control Centre, where it is only switched off temporarily.
4. Did you tap Lock iPhone? If an unlock surprises you the watch offers that button — and the next unlock then demands your passcode, by design.

What it will not do

Apple documents this as unlocking your iPhone, and that is the whole of it. Approving an Apple Pay payment or an App Store purchase is a separate authorisation and still asks for Face ID or your passcode. It does not work in reverse either: this unlocks the phone from the watch, not the watch from the phone.

Q: Why does Unlock with Apple Watch only work with a mask?
A: It is a fallback for when Face ID cannot read your face. With your face visible, Face ID handles the unlock itself.

Q: Do I need wrist detection turned on?
A: Yes. Without it the watch cannot confirm it is still being worn, so the unlock is refused.

Q: Can my Apple Watch approve Apple Pay?
A: Not through this feature. Payments and purchases ask for Face ID or your passcode separately.

Q: Which iPhones support it?
A: Any iPhone with Face ID — iPhone X or later — on iOS 14.5 or later, paired with an Apple Watch Series 3 or later on watchOS 7.4 or later.

Apple's own article is here. For more on what the Watch can do on its own, see the iWatchly apps.