On which day is a PO Box returned to sender?

A PO Box is returned to sender on the 11th day after the expiration of the rental period. This policy ensures that the postal service allows a grace period for the recipient to renew their PO Box rental before any undeliverable mail is sent back.

The 11-day timeline allows enough time for the subscriber to be notified and take action to avoid any disruption in their mail delivery. This period aligns with USPS regulations regarding the management of undelivered mail and the handling of unclaimed packages. After the 10th day, the USPS will start the process to return the items, and by the 11th day, it officially returns the undeliverable mail to the sender.