The Naval Supply Systems Command's (NAVSUP) mail-by dates for pre-Dec. 25 deliveries of holiday cards, letters, and packages has been released. A list of the mail-by dates is available on the U.S. Navy website at http://www.navy.mil/submit/display.asp?story_id=91044. All classes of mail addressed to FPO addresses must contain the New Navy Standardized Address format, which includes ship or mobile unit number, (or PSC number for ashore FPOs), virtual mail box number, and five-digit ZIP code to ensure delivery. Mail not addressed correctly could be returned to sender as undeliverable. Customers should check with local civilian or military post offices for information regarding size restrictions and customs declaration form requirements. Mailing restrictions apply, and some items cannot be mailed.
For more on shipping items, see this Military.com page.