Among the festive issue are scenes of children singing carols, posting Christmas cards and building snowmen.
Five different drawings commissioned from illustrator Andrew Bannecker were selected for the first and second class stamps.
The latest recommended posting dates for UK mail are 18 December for second class and 20 December for first.
There is no Christian imagery among the designs, as the theme for Royal Mail's main stamp issue alternates annually between secular and religious designs.
A spokesman for the company said stamps depicting Madonna and Child would also be available.
Christmas stamps were first issued in 1966 when Royal Mail ran a children's competition to select the design.
Since then the festive stamps have only been designed by children twice, in 1981 and 2013.
This year's issue will be available online and in Post Offices from Tuesday and - as with all British stamp designs - were approved by the Queen before being printed.
Andrew Hammond from Royal Mail Stamps said: "Christmas is a stamp issue we particularly look forward to and the charming style of these designs sets the perfect tone for the festive season."
There are no deliveries on Christmas Day, Boxing Day, New Year's Day or, in Scotland, on 2 January.
Royal Mail said last December it delivered 115m parcels, handling 10m on its busiest day of the month.
Royal Mail has published the designs for its 2014 Christmas stamps.