US Navy relocates nuclear attack submarine USS Jefferson City to Pearl Harbor after forward deployment in Guam.

The U.S. Navy fast-attack submarine USS Jefferson City (SSN 759) completed its official homeport change from Naval Base Guam to Joint Base Pearl Harbor-Hickam on July 9, 2026. This relocation transfers the Improved Los Angeles-class vessel from Submarine Squadron 15 to Submarine Squadron 7 to address acute fleet maintenance requirements. By basing the 34-year-old submarine in Hawaii, the Pacific Fleet trades the immediate geographic proximity of Guam for the extensive nuclear maintenance, engineering capacity, and dry-docking facilities necessary to preserve the operational availability of aging hulls.

The USS Jefferson City (SSN 759) is an active 7,038-tonne nuclear-powered submarine commissioned in 1992, equipped with 12 vertical launch system cells for Tomahawk cruise missiles and four 533 mm torpedo tubes. Its transition to Submarine Squadron 7 increases the unit to seven fast-attack submarines while keeping the overall Pacific Fleet attack submarine inventory constant.

Related topic: US Navy inactivates 46th Los Angeles-class nuclear submarine USS Alexandria after 35 years of service

The USS Jefferson City becomes the seventh fast-attack submarine assigned to Submarine Squadron 7, which operates a mixed force of Los Angeles-class and Virginia-class boats from Pearl Harbor. (Picture source: US Navy)

On July 9, 2026, the U.S. Pacific Fleet announced that the USS Jefferson City (SSN 759) completed its change of homeport from Naval Base Guam to Joint Base Pearl Harbor-Hickam, transferring from Submarine Squadron 15 to Submarine Squadron 7 after operating from Guam since 2021. The move increased Submarine Squadron 7 to seven fast-attack submarines and reduced the number permanently assigned to Guam by one, but it did not increase the Pacific Fleet’s attack-submarine inventory. The USS Jefferson City is an active Improved Los Angeles-class submarine with 34 years of service, a 7,038-tonne submerged displacement, 12 vertical launch cells for Tomahawk cruise missiles and four 533 mm torpedo tubes.

Interestingly, its relocation changes the balance between forward presence and sustainment: Guam offers shorter access to the Philippine Sea, Taiwan and the South China Sea, while Pearl Harbor offers nuclear maintenance, dry-docking, weapons support, engineering capacity and direct access to Pacific Fleet submarine command organizations. The transfer followed a Guam assignment that included Exercise Sea Dragon and the 2025 Battle Efficiency Award, indicating that the boat left Guam as an operational unit rather than as a Los Angeles submarine entering inactivation like the USS Alexandria or the USS Boise. Nevertheless, the change of homeport alters the operational cycle of the USS Jefferson City in measurable ways.

Naval Base Guam lies roughly 2,900 km from Taiwan, 2,500 km from the northern Philippines and less than 3,500 km from much of the South China Sea, allowing an SSN to reach several Western Pacific patrol areas within a few days. Joint Base Pearl Harbor-Hickam, for its part, lies roughly 6,100 km east of Guam, 8,200 km from Taiwan and more than 8,000 km from the central South China Sea. At a sustained submerged transit speed of 15 knots, the additional Pearl Harbor-to-Guam distance alone represents roughly nine days of movement, although actual transit time depends on routing, speed restrictions, training events and tactical requirements.

A Hawaii-based deployment therefore consumes more days in transit than a Guam-based deployment, reducing time on station unless the Navy extends the deployment or adjusts turnover periods. In contrast, the access to a much larger maintenance and supply system reduces the risk that a mechanical deficiency at Guam will require a 6,100 km transfer to Pearl Harbor or a longer movement to Puget Sound, San Diego or another continental U.S. facility. The USS Jefferson City was built by Newport News Shipbuilding under a contract awarded on November 26, 1984. Its keel was laid on September 21, 1987, the hull was launched on August 17, 1990, and the submarine was commissioned on February 29, 1992.

This submarine measures 110.3 m in length, 10 m in beam and 9.4 m in draft, with a light displacement of 6,000 long tons and a full displacement of 6,927 long tons, equivalent to 7,038 tonnes. Propulsion is provided by one S6G pressurized-water reactor with a D2W reactor core, two steam turbines producing 33,500 shaft horsepower, one shaft and one propeller. A 325 hp secondary propulsion motor supports limited maneuvering and emergency propulsion. Official speed exceeds 20 knots both surfaced and submerged, while the actual maximum submerged speed remains classified. Like many nuclear-powered vessels, the submarine’s endurance is limited by food, crew fatigue, maintenance condition and weapons expenditure rather than fuel, as the reactor does not require conventional refueling during a normal deployment.

The USS Jefferson City (SSN 759) belongs to the Improved Los Angeles subclass, commonly called the 688i variant, which incorporated lower acoustic signatures, strengthened under-ice capability, retractable bow planes and 12 vertical launch tubes for Tomahawk missiles. The submarine also carries four 533 mm torpedo tubes and can embark a mixed weapons load of Mk 48 Advanced Capability (ADCAP) torpedoes, Tomahawk land-attack cruise missiles, UGM-84 Harpoon anti-ship missiles and submarine-launched mines. A typical mission load is not publicly fixed because the balance between torpedoes, cruise missiles and mines changes according to tasking, but the vertical launch system (VLS) allows 12 Tomahawks to be carried without occupying torpedo-room stowage positions.

The Mk 48 ADCAP torpedo weighs roughly 1,676 kg, carries a 295 kg high-explosive warhead and is designed for use against both submarines and large surface combatants. The Block III Tomahawk, used in a 1996 combat mission, had a cited maximum range of 1,700 nautical miles, or 3,100 km. The submarine can also deploy Mk 67 mobile mines and Mk 60 CAPTOR encapsulated torpedo mines, giving it a covert minelaying role in addition to strike and sea-denial missions. The submarine’s sensor fit was originally centered on the AN/BQQ-5 active-passive sonar suite, supported by the BQS-15 detecting and ranging sonar, WLR-8 and WLR-9 electronic support receivers and the BRD-7 radio direction finding system. These systems support passive detection, target classification, fire control solution development, active ranging, interception of hostile sonar transmissions and electromagnetic intelligence collection.

Improved Los Angeles-class submarines also received later combat system, sonar processing, communications and navigation upgrades during scheduled maintenance periods. Even after modernization, the USS Jefferson City has less internal volume, electrical-generation margin, sensor aperture and payload flexibility than a Virginia-class submarine. A Block IV Virginia-class submarine displaces roughly 7,900 tonnes submerged, carries 12 Tomahawks through two Virginia Payload Tubes, and was designed with improved acoustic isolation, photonic masts, a larger special operations capacity, and greater computing growth margin. The continued use of Jefferson City therefore reflects fleet size pressure rather than technical equivalence between the two classes.

More importantly, the USS Jefferson City has a documented combat and operational record extending across more than three decades. On September 3, 1996, it fired two Block III Tomahawk missiles against Iraqi military targets during Operation Desert Strike, marking the first combat launch of submarine-fired Tomahawks since the 1991 Gulf War. The submarine subsequently supported deterrence patrols, intelligence collection, anti-submarine warfare, anti-surface warfare, and regional deployments. After moving to Guam in 2021, it operated as part of the forward-deployed submarine force under Submarine Squadron 15. Its participation in Exercise Sea Dragon placed the boat within a multinational anti-submarine warfare activity involving coordinated detection, tracking, and simulated prosecution of submarine targets by maritime patrol aircraft and partner forces.

In 2025, the submarine received the squadron’s Battle Efficiency Award, which evaluates performance across tactical proficiency, engineering readiness, navigation, communications, weapons employment, supply, training and personnel management. The award shows that the crew met squadron readiness standards shortly before the transfer, but it does not eliminate the age-related burden associated with valves, pumps, piping, electrical distribution, auxiliary machinery, sonar components and weapons-support equipment installed on a boat commissioned in 1992. Logistically, Pearl Harbor provides the maintenance depth required to keep such a submarine deployable.

Joint Base Pearl Harbor-Hickam hosts U.S. Pacific Fleet headquarters, Commander, Submarine Force U.S. Pacific Fleet, Submarine Squadron 7, Fleet Logistics Center Pearl Harbor, Pacific Air Forces headquarters, the 613th Air Operations Center, U.S. Space Forces Indo-Pacific and more than 160 commands. Pearl Harbor Naval Shipyard and Intermediate Maintenance Facility is one of four public U.S. naval shipyards capable of depot-level work on nuclear-powered vessels and the only one located between the U.S. West Coast and the Western Pacific. Its work includes reactor maintenance, dry-docking, propulsion repair, structural work, combat-system modernization, weapons support, intermediate maintenance and emergency repair.

The shipyard employs roughly 5,800 civilian workers and 500 military personnel. Its dry docks include facilities close to or above 300 m in length, but several were designed before the Virginia class and require modernization. The $3.42 billion Dry Dock 5 project, started in August 2023 and planned for completion in 2027, is intended to support Virginia-class submarines for a 150-year design life and reduce one of the Pacific Fleet’s principal maintenance bottlenecks. The reassignment also occurs during a period of sustained pressure on U.S. attack submarine force levels. The USS Alexandria (SSN 757), commissioned in 1991, was inactivated on June 29, 2026, after 35 years of service and was scheduled for decommissioning on August 4, 2026.

Its departure left 23 Los Angeles-class submarines in commission, including boats approaching or exceeding three decades of service. The U.S. Navy’s long-term force plan depends on Virginia-class construction, but annual production has remained below the two-boat rate required both to replace retiring Los Angeles-class submarines and expand the fleet. Maintenance delays further reduce operational availability because submarines awaiting depot work remain in the inventory but cannot deploy. The transfer therefore reflects a practical calculation: Guam provides superior geography for immediate presence, but Pearl Harbor offers the maintenance capacity more likely to keep a 34-year-old submarine available through its remaining service life.

Written by Jérôme Brahy

Jérôme Brahy is a defense analyst and documentalist at Army Recognition. He specializes in naval modernization, aviation, drones, armored vehicles, and artillery, with a focus on strategic developments in the United States, China, Ukraine, Russia, Türkiye, and Belgium. His analyses go beyond the facts, providing context, identifying key actors, and explaining why defense news matters on a global scale.

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