The 1918-M Sixpence was the third issue in the series to b produced at the Melbourne Mint in Australia. The Total mintage for the year was 915,000 - the second lowest mintage for the series. The type is quite scarce across all grades with mint-state examples reaching the highest values of any of the Melbourne mint-mark pieces.
In late 1915 it was decided that the production of Australia's coinage would be shifted from Britain to Australia. New dies for the Australian Shilling, Florin, Sixpence, and Threepence were produced in London for use at the Melbourne Mint with a small 'M' mint-mark. Arrangements were also made for Australia's bronze coins to be manufactured at the Calcutta branch of the Royal Mint. The production of Silver Coinage at the Melbourne Branch of the Royal Mint began on the 12th of January 1916.