Unlocking an August Smart Lock with your phone is easy enough, but if you have an Apple Watch, you don't even need to have your phone with you. Apple's smartwatch can now unlock any August-branded smart lock, so long as you're specified as its "owner." To set it up, you first need to make sure your wearable is running WatchOS 4 or higher and that it has the new native August Apple Watch app.
You'll also need to update your iOS app, because you might be prompted to log in to sync your locks. Once that's done (and you're a recognized owner), though, you'll be able to view all the August locks you have on the Watch's screen. If you want easy access to a specific lock, you can even add it as a Watch face shortcut. August Home says it's a different feature from Auto-Unlock, since you'll still have your phone nearby with that one. With this particular feature, all you'll really need is Apple Watch itself.