Only one Australian submarine is fully operational as the aging fleet undergoes emergency maintenance.

The Royal Australian Navy has only one fully operational submarine left, while the rest of the aging Collins-class fleet is undergoing emergency repairs or awaiting completion of planned upgrades.

Australia currently has a fleet of six Collins submarines, which have been gradually entering service since 1996 but have recently encountered problems including “unprecedented” hull corrosion.

Defense sources confirmed to the ABC that two Collins submarines are currently stationed at the Osborne shipyard in Adelaide, where strikes are causing delays in extensive maintenance known as “full drydocking”.

The country’s three other submarines are stationed at Garden Island Naval Station in Western Australia, but the Department of Defense insists at least one of the boats could be put to sea if needed urgently.

In its statement, the Ministry of Defense insists it has “more than one boat” available for operations “if necessary”, although the ABC understands at least one of those submarines has not yet been certified to return to service.

“Defence continues to meet the Government’s target level of operational readiness for Collins class submarines. The MoD has more than one boat available for operations if required,” a MoD spokesman told the ABC.

“For operational security reasons, Defense does not confirm the exact location and availability of specific platforms,” the spokesperson added.

In May, the Australian Submarine Corporation (ASC) told a parliamentary hearing that half of the Collins fleet would remain out of the water until the end of the year after unprecedented corrosion problems were discovered on two aging boats.

Workers have since gone on strike at government-owned ASC Adelaide, continuing their long-running pay equality dispute with ASC workers in Western Australia.

The Albana government has not yet commented on the limited availability of Australian Collins-class submarines.

Under the AUKUS partnership, US and British nuclear submarines are due to begin withdrawing from Western Australia from 2027, with Australia expected to receive its first Virginia-class submarines in the 2030s.