Below is press release of the US Navy's policy on sending mail to the service member.
The Navy announced Friday via a fleetwide message that the entire code — the traditional 5-digit ZIP and the “+4” numbers, separated by a dash — must be included for mail to reach any mobile fleet post office.
“Mail not addressed correctly, including mail already en route, will be returned to sender as undeliverable,” according to a Navy news release put out Monday.
The change comes as a result of new U.S. Postal Service procedures regarding military mail processing, according to the release. The nine-digit ZIP on all correspondence will be read by “USPS automated equipment,” the release said — anything without all the numbers gets sent back.