3 RAR traces its lineage to 1945 and has seen operational service in Japan, Korea, Malaya, Borneo, South Vietnam, Rifle Company Butterworth, East Timor, the Solomon Islands, Afghanistan, and Iraq.

Commanded by Lieutenant Colonel Charles Green, it attacked and captured a large North Korean defensive line in a combined arms operation with tanks and artillery.

[8] Over the period 3–8 October 1951, 3 RAR fought the Battle of Maryang San, which is widely regarded as one of the Australian Army's greatest accomplishments of the Korean War.

However, it was not until October 1957 that 3 RAR arrived in theatre; it then commenced a period of acclimatisation at the FARELF Training Centre Kota Tingi (later to become the Jungle Warfare School).

3 RAR then moved to company base camps at Kuala Kangsar (BHQ), Lasah, Sungei, Siput, Penang and Lintang.

It remained there for four years during which time it carried out routine training and barracks duties and was organised on the Pentropic establishment, with five rifle companies and an enlarged headquarters.

[11] 3 RAR also served in Malaysia and Borneo during the Indonesia-Malaysia Confrontation and was involved in a series of highly successful cross-border missions under Operation Claret.

[11] 3 RAR served two tours in South Vietnam, the first from December 1967 with the battalion stationed in Phuoc Tuy province as part of the 1st Australian Task Force.

As the ready reaction force at the 1ATF base 'A' Company 3 RAR was responsible for clearing and securing the nearby provincial capital of Bà Rịa during the Tet Offensive of February 1968.

[15] During 26–28 May 1968, 3 RAR, while stationed at FSB Balmoral in a battalion defensive position, withstood two determined assaults by regimental sized units of the North Vietnamese People's Army of Vietnam (PAVN) during the Battle of Coral–Balmoral.

[17][18] On 8 May 1970 a group of soldiers from 3 RAR who had served in South Vietnam attacked 1,000 Moratorium marchers who were peacefully protesting against the war in Adelaide.

From 1989, 3 RAR formed the main combat elements of the Parachute Battalion Group, which also included an engineer troop from 1st Field Squadron, signals detachment from 104th Signal Squadron, artillery fire support from 'A' Field Battery, 8th/12th Regiment and medical support from the 1st Parachute Surgical Team.

The Battalion later deployed to the enclave of Oecussi where, in early 2000, it encountered the greatest level of pro-Indonesian Militia activity it had seen since the previous year.

The 3 RAR company of soldiers consisted of approximately 100 personnel to provide added support to the local and Australian Federal Police in enforcing the rule of law and restoring order in the Solomon Islands.

[38] In late 2003, 3 RAR was warned to provide a Company Headquarters and a four rifle section platoon for security duties in Iraq on Operation Catalyst.

On 13 April 2004 SECDET elements were involved a very successful contact when an ASLAV engaged a mortar base plate that was firing on the Green Zone.

Both tours were eventful with several contacts, a rocket attack that injured four soldiers, and the accidental death of Private Jacob Kovco in April 2006—Australia's first casualty in Iraq and the subject of intense media attention.

[51] The battalion was warned for Operation Okra in 2017 which saw the unit's command element and Alpha Company deployed as part of the fifth rotation of Task Group Taji.

[citation needed] In 2017 3 RAR deployed Bravo Company to Kabul Province, Afghanistan as part of Force Protection Element 8.

[citation needed] In 2017, it was announced that 3 RAR would re-role as a mechanised infantry battalion under the workforce alignment of Plan Beersheba to be equipped with M113AS4 Armoured Personnel Carriers.

The contingent – made up mostly of soldiers from 3RAR – joined Australian Federal Police officers and supported critical infrastructure in the capital Honiara.