She was named for the Diamantina River in Queensland, and was one of eight River-class frigates built for the RAN during World War II.

[3] After transporting several high-ranking officers to Saposa Island, Diamantina was committed to the Bougainville Campaign, providing fire support to the Australian Army units operating ashore in July and August 1945.

[4] The frigate carried Lieutenant General Kanda and Vice Admiral Baron Samejima, officers of the Japanese Imperial High Command to the surrender of Torokina on 8 September 1945.

On 20 September, the ship performed the first survey of the Montebello Islands following the British atomic test, Operation Hurricane.

Based in Fremantle, Diamantina remained in service as an oceanographic vessel until 1980;[3] she briefly interrupted these duties in March 1963, escorting the royal yacht during Queen Elizabeth II's tour to Australia.

[8] Diamantina paid off from the RAN on 29 February 1980, and was the last World War II-era frigate to serve Australia.

[8] In March 2006, Diamantina left her berth for the first time in 25 years when she was towed out into the river to allow repairs to the dock,[11] which had been flooded since the seals failed in 1998.