South West Africa was the name that was used for the modern day Republic of Namibia and became part of the Union of South Africa in 1910
The postal history of South West Africa begins with the South African Armed Forces defeat of the Imperial German army in the colony of German South West Africa in 1915
Between 1923 and 1952 South African stamps were overprinted with South West Africa and Zuid West Africa or simply SWA. Stamps directly stating they were South West African stamps (also marked Suidwes-Afrika) were also issued
In 1989 the last stamps were issued by South West Africa were a set of 15 (ten depicting minerals: gypsum, fluorite, mimetite, cuprite, azurite, boltwoodite, dioptase, diamond, wulfenite and gold, and five illustrating types of mining at different mines: Oranjemund, Tsumeb, Rosh Pinah, Uis and Rossing).
These stamps were unusual in that only a short while after their issue the illegal Republic of South West Africa was declared independent becoming Namibia. As the stamps were new most of the designs were kept with only the name changed (cuprite was dropped and willemite added for the Namibian issue). Another problem was that one of the stamps - the boltwoodite one - had an error in its chemical equation. This was corrected in the Namibian issue