How do I return lost iPhone back to its owner?

Apple doesn't handle that sort of thing. If there isn't any personally-identifying information on it you can access, take it to the local police, or if applicable, the Lost & Found department of the facility involved.

For reference, the people on these boards are mostly other customers.

(260910)

First off, thank you for doing the right thing and trying to return this lost iPhone to the owner. Unfortunately because there are so many thieves in this situation that don’t do the right thing, makes contacting the original owner difficult as they have received threats to remove Activation Lock.

• Leave the iPhone plugged in for a few days to see if anyone calls.
• Open the Medical ID to see if there are Emergency Contacts you can reach.
• Try asking Siri to call generic names, “Mom”, “Dad”, “Husband”, “Wife”.
• Take a photo with the iPhone of your name and phone number, which if they have iCloud Photos turned on it will sync to their devices to which they will hopefully see.

If all else fails, you are best as stated leaving it if you found it at an establishment’s Lost and Found, or the local law enforcement station where once you have it charged they can view the location via Find My and go to pick it up there. Thank you again.