The Federal Government has confirmed that a long-awaited upgrade program for Australia’s aging Collins-class submarines will begin at the end of May.
The move is seen as a critical step in maintaining the Royal Australian Navy’s underwater warfare capability ahead of the transition to nuclear-powered submarines under AUKUS.
The first submarine to enter the Life of Type Extension (LOTE) program will be HMAS Farncomb, with work to be undertaken at ASC’s Osborne shipyard in Adelaide.
The overhaul is expected to take around two years per vessel, although Farncomb’s refit may take longer as engineers conduct a detailed assessment to guide upgrades for the remaining fleet.
Originally envisioned as a comprehensive modernisation package, the LOTE program has since been scaled back. Defence officials now describe the work as an “enhanced sustainment” effort rather than a full systems upgrade.
When the project was first proposed in 2020, plans included integrating Tomahawk land-attack cruise missiles and installing a new Thales advanced periscope and mast system.
However, both upgrades were abandoned in 2024 after Defence determined they posed too much technical and schedule risk.
Other ambitious plans also appear to have been reduced in scope. Earlier proposals involved cutting the submarines’ hulls in half to replace diesel and electric propulsion systems, along with major power conversion and distribution upgrades.
Cooling system improvements and extensive hull assessments were also planned.
Despite the reduced scope, the total projected cost of the program has climbed significantly — from an estimated $6 billion in 2020 to approximately $11 billion today — with the entire effort expected to continue through until 2034.
The Collins-class submarines entered service between 1996 and 2003 and have remained in operation far longer than originally intended due to repeated delays in selecting and building a successor fleet.
Successive governments have shifted course several times over the past decade. In 2014, the Abbott Government explored acquiring Japanese Sōryū-class submarines before abandoning the plan in favour of the French-designed Attack-class submarines in 2016.
That program was itself scrapped in 2021 when Australia entered the AUKUS security pact with the United States and United Kingdom.
Under AUKUS Pillar I, Australia is expected to acquire US nuclear-powered submarines from the early 2030s, followed by a new class of Australian-built nuclear-powered submarines based on a British design in the 2040s.
In the meantime, maintaining the Collins-class fleet has become increasingly difficult, with usually only two or three of the Navy’s six submarines operational at any one time.
The issue became so severe that the Collins-class fleet was reinstated to the Federal Government’s Projects of Concern list in late 2024.
Defence Minister Richard Marles recently described the submarines as experiencing “periods of near zero operational availability with an extensive range of faults and deficiencies.”
Mr Marles says extending the life of the fleet was essential to preserving Australia’s defence capability during the transition to nuclear-powered vessels.
“Extending the life of all six Collins-class submarines is critical to maintaining that edge as we transition the Navy from conventional to nuclear-powered submarines,” he said.
Defence Industry Minister Pat Conroy said the program would also support Australia’s sovereign defence industry and submarine supply chain.
“Strong collaboration with Defence industry partners will be essential to keeping the Collins class fleet available as we move towards a nuclear-powered submarine capability,” Mr Conroy said.
The government has indicated it will stagger submarine refits to ensure at least two boats remain operational throughout the upgrade period.
