Watch Unlock is one more secure way to unlock your smartphone
With Wear OS 4, Google added the ability to unlock an Android smartphone that is paired with a smartwatch. This is similar to how an Apple Watch could unlock a paired iPhone. Effectively, you don't need to enter a PIN/password or biometric information to unlock the phone while wearing a Wear OS 4 smartwatch. This is a handy feature as you can unlock your phone when your fingers are wet or dirty, or you're wearing a helmet and can't use Face Unlock. This feature isn't available yet, and could be released with a future software update.
Android enthusiast Mishaal Rahman discovered this feature a few days ago for the Pixel Watch. However, it looks like it will be available to all Wear OS 4-based smartwatches, including the Galaxy Watch 4, Galaxy Watch 5, and Galaxy Watch 6. Later, Ærmando discovered the Watch Unlock feature (com.google.android.clockwork.active_unlock) in the One UI 5 Watch update.
Watch Unlock is not the same as Trusted Devices, a feature available on Android devices for years. Watch Unlock is a more secure method, and it can actually unlock a paired phone, provided that the smartwatch itself is unlocked using a PIN or other authentication method. To use this feature, you must set a PIN or password for your Wear OS smartwatch.
