Will Face ID work with a mask? Can I wear a mask with Face ID? How does Face ID unlock with a mask on? Is my iPhone secure if I use Face ID with a mask?
Yes, it's possible to train Face ID to work while a face mask is being worn. The trick is to create an alternative appearance under Face ID & Passcode settings. Some have already noticed that if you wear a mask during the setup process, Face ID won't recognize your face for scanning.
While Face ID is scanning your appearance, you must cover only half of your nose and mouth with a mask folded in half, or with a sheet of paper. There are many examples of Face ID mask training on YouTube. Once completed, Face ID will unlock the iPhone as normal even when a mask is worn.Using Face ID with a mask can simplify iPhone use for healthcare workers and others, without resorting to a passcode.
Note: it's not clear how training Face ID to work with an obstructed face affects the level of security. It's possible that partially obstructing your face increases the chance someone else could unlock your device.