The Australian Army has operated M113 armoured personnel carriers since 1964. An initial pair of M113s was purchased for trials purposes in 1962. Either 817 or 840 were acquired by 1979, comprising nine different variants. A long-running modernisation program that commenced in the 1990s resulted in 431 M113s being upgraded between 2007 and 2012. All of the upgraded M113s remain in service as of 2020.