Postal services in Andorra are unique in that they are not operated by the country itself, but by its two larger neighbouring countries, Spain and France.[1] This is a legacy of the centuries of de facto control exercised by those two countries over Andorra. Correos of Spain and La Poste of France operate side-by-side. However, the postal code system, introduced in July 2004,[2] has a different format from those of either Spain or France, consisting of the letters "AD", followed by three digits.[1]
Both postal administrations issue their own postage stamps for use in Andorra featuring unique designs,[3] as those of Spain and France are not valid.[4] These are used for international correspondence, as postal service within Andorra is free.[5]