This is an overview of the postage stamps and postal history of Australia.
The various colonies that joined to form the Commonwealth of Australia in 1901 had long operated their own postal systems; see the articles on the systems of New South Wales, Queensland, South Australia, Tasmania, Victoria, and Western Australia for the respective details. At federation the Commonwealth was granted the power to operate a central postal system through Section 51(v) of the Australian Constitution. Although unification of systems was expected to occur quickly, and a federal postmaster general was appointed, the process was delayed for several years; the stamps of each colony were not recognized by other colonies until 1910, and postal rates only became uniform throughout Australia on 1 May 1911. The Postmaster-General's department eventually became Australia Post in the 1970s - see that article for more details of the organizational aspects of Australia's postal system.
Although one-penny postcards and lettercards appeared in 1911, for most students of the area, Australian philately proper begins in early 1913 with the Kangaroo and Map series of stamps, featuring a kangaroo standing on a map of Australia, and inscribed "AUSTRALIA POSTAGE". The first issue of the series consisted of 15 values ranging from a half penny to two pounds. The watermark was the first of several variations on the "A surmounted by a crown" theme, in this case the "wide crown and wide A". Kangaroo and Map stamps were reprinted several times: in 1915 with first the "wide crown and narrow A" watermark, then the "narrow crown and narrow A"; in 1929 with the "multiple small crown and A" watermark, and higher values in two colors; in 1932 with the "multiple small crown and C of A" watermark. In December 1945 the series ended with a redrawn two-shilling stamp. Most of the Kangaroo and Map stamps are readily available today, although values of 5 shillings and up are expensive.
1913 also saw the first profile of King George V, a one-penny value in carmine. A cleaner version of the design was issued in 1914, and various denominations appeared from time to time, along with changes of watermark, as late as 1932. A 6-penny stamp depicting a kookaburra appeared in 1914 as well.
The Commonwealth's first commemorative stamp was issued on 9 May 1927 to mark the opening of Parliament House in Canberra. Commemmoratives began appearing regularly in the 1930s, typically as sets of two to four of the same design, with the low value common and the higher values issued in much smaller numbers.
The accession of George VI in 1937 was the occasion for a new definitive series of 14 designs, featuring both portraits of the new King and Queen, as well as Australia's unique animals, including the kangaroo, kookaburra, koala, platypus, and the commercially important Merino sheep. In 1938 the King and Queen portraits on the low values were re-engraved for improved appearance, and in 1942 they were superseded by new designs, along with a 5 1/2p value depicting an emu.
New definitives from 1950 on showed an older George and Elizabeth, then gave way in 1953 to a profile of Elizabeth II. 1953 also saw the curious "PRODUCE FOOD!" stamps, depicting scenes from the butter, wheat, and beef industries, and issued to encourage food production. A 1956 issue for the Olympic Games being held in Melbourne included early examples of stamps printed in full color, and in 1957 Australia's first Christmas stamp began an annual tradition.
The definitive series of 1959 used various portraits of the Queen for its low values, and a variety of plants and animals for the higher ones. Fluorescent paper began to be used in the 1960s. A series of 1963 included birds and well-engraved portraits of early explorers and their ships for values going up to two pounds.
The introduction of decimal currency necessitated a new series of definitives in 1966. Values from 1c to 5c used the same portrait of the Queen, in different colors, while higher values included sea life in addition to the 1963 designs redrawn with decimal values; for instance, the 4-shilling Abel Tasman of 1963 became a 40c stamp of 1966.
Stamp-issuing policy was relatively restrained in the 1970s, but in the 1980s and 1990s, considerable numbers of stamps began to appear, and many miniature sheets were overprinted for local stamp shows.
Old Australian Postboxes found at the Australian National Museum