During 1964–65 the regiment provided most of the men for 1 Troop, A Squadron, 4th/19th Prince of Wales Light Horse, which was subsequently equipped with the new M113A1 Armoured Personnel Carrier (APC) and was deployed on active service to South Vietnam in May 1965. In October 1967 the Australian government announced it would increase the size of the 1st Australian Task Force (1 ATF) at Nui Dat in Phuoc Tuy Province from two to three infantry battalions, while additional supporting arms, including a tank squadron would also be added to the force. As such in February 1968, C Squadron was sent to Vietnam, with a total strength of 20 Centurion tanks which would work closely with the M113s of the 3rd Cavalry Regiment. However, two of the four tank troops were initially held back until the Centurions had proved themselves capable of operating in the conditions. The tank squadron reached full strength on 5 September 1968. Meanwhile, in May the regiment had again reached full strength, with A Squadron re-raised in order to meet the ongoing operational commitment.