While the earphones themselves don’t have built-in GPS, Apple is able to guesstimate their location based on the last time they were in Bluetooth range of your own device. You’ll see them plotted in a map, as with a lost iPhone, albeit with less precision.
But lets say the other, more likely scenario, where you only lose a single AirPod within your own home. If they’re in Bluetooth range and have enough of a charge, you’ll be able to ring an sound that will cost the lost Airbud to chirp.
If your AirPods are out of battery though, you’re out of luck. It’s also not clear how Apple handles losing a single AirPod out of Bluetooth range, but I imagine it’s the same as losing the entire kit.
It’s a welcome feature that’s a much better alternative to paying up $69 for a replacement. Frankly, it’s a little surprising Apple didn’t implement it at launch (especially given the hefty delay), but better late than never. And if you’re worried about someone stealing your AirPods, may I suggest a dental floss disguise?