AUKUS Explained: Submarines and Advanced Capabilities
AUKUS pairs Virginia-class submarine sales to Australia with a second advanced-capabilities track. Defense ministers reaffirmed both pillars in December 2025.
WASHINGTON, Nov. 6, 2026 — Australia, the United Kingdom and the United States announced the AUKUS security partnership in September 2021. The arrangement has two main lines of effort, which official documents call pillars. A joint statement issued after a Dec. 10, 2025, meeting at the Pentagon said U.S. Secretary of War Pete Hegseth hosted Australia’s Richard Marles and the United Kingdom’s John Healey to reaffirm the partnership. The statement singled out “submarine cooperation under AUKUS Pillar I” as critical to a “robust deterrent” and “advanced capabilities development under AUKUS Pillar II.”
The Congressional Research Service, in a report updated Jan. 26, 2026, describes Pillar 1 in three parts. The partners plan to rotationally deploy four U.S. attack submarines and one British attack submarine from a port in Western Australia. The United States plans to sell Australia three to five Virginia-class submarines and later build three to five replacement boats for the U.S. Navy. The United States and the United Kingdom are also to help Australia build additional boats of a new British-Australian design, called SSN AUKUS, toward a planned eight-submarine Australian force.
Industrial limits, and what the ministers reaffirmed
Congress approved enabling legislation for Pillar 1 in the fiscal 2024 National Defense Authorization Act (P.L. 118-31), in provisions CRS identifies as Sections 1351-1354. CRS reported that 41 Virginia-class boats had been procured through fiscal 2025. When bought at a rate of two per year, the Navy’s fiscal 2026 budget submission put their estimated procurement cost at about $5.0 billion each. Actual construction, however, has not kept pace with that two-a-year procurement rate. Since 2022, CRS reported, production has been limited to about 1.1 to 1.2 boats per year, leaving a growing backlog of boats that have been bought but not yet built.
Those industrial-base numbers are the practical constraint on Pillar 1’s submarine timeline. Selling boats to Australia, CRS notes, would reduce the size of the U.S. attack-submarine force until replacement boats are built. The Navy and industry have said they are working toward a production rate of 2.0 boats per year and, later, 2.33 boats per year, a figure the Navy has tied to replacing boats sold under AUKUS and to working down the backlog.
In June 2025, CRS reported, the Defense Department began a review of Pillar 1. In early December 2025, after the study was completed, Trump Administration officials publicly affirmed support for AUKUS, including Pillar 1. The Dec. 10 joint statement then said the three defense chiefs intended to move “full steam ahead,” including on infrastructure and workforce improvements for a trilateral submarine industrial base, and to accelerate Pillar II projects “with particular focus on near-term warfighting objectives.”
The public record, as of those two documents, is a partnership with a detailed submarine plan and a less detailed advanced-capabilities track, reaffirmed by ministers in December 2025, and bounded by a U.S. shipbuilding rate that CRS says has not yet reached the pace the plan assumes. Alliance coverage continues on the AUKUS hub and the Australia and United Kingdom country pages. Related reporting includes the first island chain and alliances.
Sources
- U.S. Department of War: AUKUS Defense Ministers’ Meeting Joint Statement (Dec. 10, 2025)
- Congressional Research Service: Navy Virginia-Class Submarine Program and AUKUS Pillar 1 (RL32418)
