The MOD free Christmas mail service for forces families opens on 27 October and runs until 24 November.
Customers should hand in their parcels at a UK post office or overseas Forces post office, and hold on to their certificate of posting.
Packages must be no heavier than 2kg and cannot contain items like alcohol or aerosols. They should carry a fully completed CN22 customs declaration with the gift declaration box ticked.
Service families will be able to send a Christmas present to loved ones based in the Falklands, Ascension or Diego Garcia free of charge during this time, after which entitlement to a free small parcel service will cease.
BFPO numbers that have been added to the free Christmas mail service are 485, 494, 655, 677 and 678.
The latest Christmas posting date for all mail from the UK to personnel on operations is 17 November. Mail to static firm bases and permanent joint operating bases should be posted by 24 November.
The deadline for all overseas locations to send mail home in time for Christmas delivery is 17 December. This is to allow time for it to be transferred into the civilian service or processed through the Royal Mail Worldwide Distribution Centre at Heathrow.
The Government provides detailed information on measurements, restricted items and instructions on how to use BFPO.