10-cent flag, 1965

The story of the postage stamps and postal history of Tanzania begins with German East Africa, which was occupied by British forces during World War I. After the war, the territory was named Tanganyika and issued stamps under that name until after a union with Zanzibar in 1964.

The first issue of Tanzania proper was a set of four commemorative stamps marking the union, issued 7 July 1964. Inscribed "UNITED REPUBLIC OF TANGANYIKA & ZANZIBAR", two values depict a map of the coast from Tanga to Dar-es-Salaam along with Zanzibar and Pemba, while other two show hands holding a torch and spear.

1-shilling stamp of 1965, used at Shinyanga probably in 1968. Note that the postmark still gives "Tanganyika" as country name.

The first definitive series was issued 9 December 1965, and consisted of a set of 14 values ranging from 5 cents to 20 shillings, depicting a variety of scenes, symbols, and wildlife.

The stamps of Tanzania were also valid in Kenya and Uganda (until 1976), and so Tanzania did not typically issue its own commemoratives. A definitives series issued 9 December 1967 featured various fish, and series of 15 stamps from 3 December 1973 depicted butterflies. Four of these values were surcharged 17 November 1975.

In 1976 and 1977, Tanzania issued eight commemorative sets that shared design with the stamps of Kenya, and after that it issued its own designs.

5-shilling stamp of 1980 depicting lion and cubs, used in 1985

Stamp-issuing policy was relatively restrained in the 1980s, with about 7-8 special issues each year, typically of four stamps each, and a definitive series of mammals in 1980, but by the end of the decade the postal administration had begun putting out large numbers of issues aimed solely at stamp collectors, with averages of over 100 types annually.