Mabo Day occurs annually on 3 June. It commemorates Eddie Koiki Mabo c. 29 June 1936ââ¬â21 January 1992 a Torres Strait Islander whose campaign for Indigenous land rights led to a landmark decision of the High Court of Australia that, on 3 June 1992, overturned the legal fiction of terra nullius which had characterised Australian law with regards to land and title since the voyage of James Cook