The Seamen's Union of Australia was the principal trade union for merchant seamen in Australia from 1876 to the 1991. Australian seamen were forerunners of maritime trade unionism. Efforts to form trade unions amongst merchant seamen trading out of Australian ports can be traced back to 1874, with the formation of the Sydney Seamen's Union and Melbourne Seamen's Union. The trade unions of this period inspired, amongst others, J. Havelock Wilson of the British National Union of Seamen, who served on Australian coasting vessels for a period in the late 1870s.