The United States Navy decommissioned the nuclear-powered attack submarine USS San Juan (SSN-751) on Thursday, marking the end of its 38-year service as the first Improved Los Angeles-class submarine. The ceremony took place at the US Naval Undersea Museum in Keyport, Washington. Commissioned in 1988, San Juan was the first of 23 Improved Los Angeles-class subs and introduced several technological advancements. However, its retirement signifies a growing gap between aging attack submarines leaving service and Virginia-class replacements entering the fleet. The Navy aims to maintain about 66 nuclear-powered attack submarines, but the force is projected to shrink from approximately 49-50 boats in 2025 to around 46-47 by 2030. This shortfall is not only due to the number of subs but also the increasing maintenance requirements for aging Los Angeles-class boats and the competition for nuclear-qualified workforce and shipyard capacity with Virginia-class attack submarines and Columbia-class ballistic-missile submarines. The USS San Juan, built by General Dynamics Electric Boat, was a technological bridge to Virginia-class submarines, equipped with retractable bow diving planes, additional noise-reduction measures, and the AN/BSY-1 combat system. San Juan demonstrated its capabilities in 1993 when it conducted the first through-ice surfacing by a 688i submarine. Throughout its service, San Juan reflected the evolving role of US attack submarines, from anti-submarine warfare to multi-mission platforms for submarine hunting, intelligence gathering, anti-surface warfare, and land attack. Its final operational deployment covered nearly 37,600 nautical miles before entering Reserve, Stand Down status in August 2024 and decommissioning shortly after. The retirement of the USS San Juan highlights a more significant concern - the pace at which Los Angeles-class submarines are retiring compared to Virginia-class deliveries. With most surviving boats now over three decades old, their continued operation is increasingly expensive and maintenance-intensive. The US built 62 Los Angeles-class submarines between 1972 and 1996, and the fleet could fall to roughly 45-47 boats around 2030-31 before gradually recovering. Meanwhile, Virginia-class deliveries lag behind retirements due to production inconsistencies, compounded by the Columbia-class programme's demands on the submarine industrial base. The US Navy is facing additional pressure from AUKUS, an alliance with Australia that could eventually lead to Australia acquiring three to five Virginia-class submarines from the United States.