During her career, Onslow became the first conventionally powered submarine to be fitted with anti-ship missiles, and was successful in wargames, "sinking" a seven-ship flotilla during Exercise Kangaroo 3 in 1980 and the United States supercarrier USS Carl Vinson at RIMPAC 1998.

[1] Onslow has a maximum range of 9,000 nautical miles (17,000 km; 10,000 mi) at 12 knots (22 km/h; 14 mph), and a test depth of 200 metres (660 ft) below sea level.

[8] On board was Vice Admiral Sir Victor Smith, at the time the Chief of Naval Staff, who had embarked at Brisbane.

[13] During the exercise, a practice torpedo fired by the United States Coast Guard Cutter Rush[14] failed to disengage as designed and hit the submarine—the only damage was a small dent near the stern.

[15] During another ANZUK deployment, in 1974, the boat's attack periscope was damaged when it came in contact with the log probe of the frigate HMS Leopard.

[16] In 1977, Onslow was presented with the Gloucester Cup, marking her as the most efficient warship in the RAN during the previous year—Onslow was the first submarine to receive the award.

[17][18] Upon returning to base, doctors found that one-third of the 66 survivors had absorbed twice the lethal limit of carbon monoxide into their blood.

[17] The crew onboard were taken to Soldiers Beach surf club and provided with free alcohol for 3 days before returning back to duties.

The RAN Board of Inquiry into the incident concluded that the accident was caused by human error—the duty engineer failed to shut down both engines—but members of Onslow's complement disagree with this, claiming the problem to be mechanical in origin.

[17] When interviewed by Sunday Night in March 2009, the deputy Chief of Navy, Rear Admiral Davyd Thomas (who had been Passlow's divisional officer prior to the incident) promised counselling for the survivors, and claimed that prior treatment of the Onslow submariners was due to a limited understanding of post-traumatic stress disorder back in the 1980s.

[4] As part of the modernisation, integrated data processing and fire control systems were installed, and the boat was fitted with Micropuffs passive ranging sonar.

[4][5] Onslow was the first Australian submarine to visit the west coast of the United States of America when she arrived in San Diego on 17 July 1985.

[22] Australian Defence Industries (ADI) was awarded the $100 million refit contract for Onslow and sister submarine HMAS Otama in July.

[25] During this particular ceremony, normally intended to induct new sailors into the 'court of King Neptune', the victims were verbally and physically abused, had their pelvises and genitals covered in what was described as a "blistering concoction", then thrown overboard and forced to stay there until the rest of the company permitted them on board.

[25] When one of the victimised sailors complained to superiors, he became subject to several administrative errors and inconveniences, to the point where he was forced to resign a year later.

[26] The inquiry also stated that while line-crossing ceremonies would continue to be held aboard RAN vessels, they would be supervised by a non-involved member of the crew to prevent similar extreme situations developing.

[27] On the evening of 16 April 1997, three Australian Special Air Service Regiment soldiers were injured when they were thrown from their Zodiac boat during launch and recovery exercises with the submarine.

[3] The submarine had to pull out of the early part of the exercise: a resistor in the motor room switchboard had begun to smoke, forcing Onslow to return to Pearl Harbor for repairs.

[33] Onslow operated on a secret patrol course 130 nautical miles (240 km; 150 mi) south of Kangaroo Island while aircraft from the competing Australian, British, Canadian, and New Zealand air forces attempted to locate and 'sink' her.

[43] Another docking occurred on 18 May 2012, with hull cleaning, rust removal, repainting, and repairs to the boat's aft torpedo tubes done before she returned to display on 6 June.