GAO: US attack sub maintenance delays cost $3.4 billion, 15,000 lost operational days
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Maintenance delays for U.S. Navy attack submarines cost an estimated $3.4 billion over the last decade and resulted in 15,000 lost operational days between 2016 and 2025, the Government Accountability Office reported. The backlog left fully crewed submarines pier-side, unable to deploy, with active idle time costing up to $237,000 per day for Virginia-class boats. Shipyard delays in decommissioning nuclear submarines added $722 million in costs from 2016 to 2025.
Key Facts
- The GAO estimates maintenance delays for attack submarines cost $3.4 billion over the last decade.
- Between 2016 and 2025, attack submarine maintenance backlogs resulted in 15,000 lost operational days.
- Active idle time costs $220,000 per day for Los Angeles-class submarines and $237,000 per day for Virginia-class submarines.
- Shipyard delays in decommissioning nuclear submarines cost $722 million from 2016 to 2025.
- The USS Pasadena became inactive in January 2025 and is not expected to enter Norfolk Naval Shipyard until November 2028.
Maintenance Backlog Costs
Over the last decade, maintenance delays for U.S. Navy attack submarines resulted in an estimated $3.4 billion in costs to sustain crews and submarines that provided no operational capability, according to the Government Accountability Office. Between 2016 and 2025, maintenance backlogs for attack submarines resulted in 15,000 lost operational days, including active idle time when submarines and their crews must remain pier-side because they are no longer certified to conduct normal operations and cannot be inducted into a maintenance period. For Los Angeles-class submarines, active idle time is costing almost $220,000 per day for the entire group, while for the Virginia-class, that figure is more than $237,000 per day. Diana Maurer, a director of GAO's Defense Capabilities and Management team, described the situation as 'essentially a traffic jam — subs waiting to get into dry dock for depot maintenance.'
Inactive Idle Time
Shipyard delays in decommissioning nuclear submarines have cost $722 million from 2016 to 2025, with inactive idle time meaning boats must remain pier-side until a shipyard has the capacity in a dry dock to defuel their nuclear reactor. The Los Angeles-class submarine USS Pasadena became inactive in January 2025 but is not expected to enter Norfolk Naval Shipyard for almost four years, until November 2028. During this time, the attack submarine is unable to be operational since its dive certification is expired, but is still fully crewed with sailors, GAO noted. While the Navy will use the boat as a training platform, GAO estimates the delay will cost more than $300 million.
Future Projections
GAO credits the Navy with making progress in reducing active idle time, but warns that inactive idle time for submarines has grown and is projected to worsen. Given current trends, the Navy will be stuck with 15 submarines and 14,000 days of inactive idle time between 2026 and 2030, at an estimated cost of $3.1 billion. Maintenance for nuclear submarines is performed at four public shipyards: Portsmouth Naval Shipyard, Norfolk Naval Shipyard, Puget Sound Naval Shipyard, and Pearl Harbor Naval Shipyard. Certain maintenance can also be done at two private shipyards: General Dynamics Electric Boat in Groton, Connecticut, and Huntington Ingalls Industries Newport News Shipbuilding in Newport News, Virginia.
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GAO: US attack sub maintenance delays cost $3.4 billion, 15,000 lost operational days
