The U.S. Navy’s schedule for getting USS Connecticut, one of its prized Seawolf class nuclear attack submarines, back into service has slipped into next summer. The boat suffered severe damage, especially to its bow, in a collision with an underwater seamount in the South China Sea in 2021. The service had previously hoped that repairs would be finished before the end of this year, and planning is also now underway for the submarine’s retirement in 2031. This would mean it could serve for just four years before being pulled from service once and for all.

“USS Connecticut (SSN 22) is currently undergoing a complex Extended Docking Selected Restricted Availability (EDSRA) at Puget Sound Naval Shipyard & Intermediate Maintenance Facility. Current work consists of structural and systems restoration and required lifecycle maintenance,” a Navy official told TWZ today. “The Navy’s target completion date for the availability is the summer of 2027. PSNS & IMF is dedicated to executing this work with the highest standards of safety, technical accuracy, and craftsmanship to ensure the ship returns to the fleet ready to take its place at the tip of the spear in defense of our nation’s interests.”

USS Connecticut is the second of just three Seawolf class submarines commissioned between 1997 and 2005, the others being USS Seawolf and USS Jimmy Carter. The Jimmy Carter, which came last, is a one-of-a-kind subvariant of the design that is optimized for underwater espionage missions. However, the Seawolf and Connecticut also feature advanced capabilities compared to other submarines in the Navy’s inventory today, and the service utilizes all three for a variety of specialized tasks, for which they are in very high demand.

After USS Connecticut hit the seamount in October 2021, the submarine first limped to Guam, and then made its way to San Diego in southern California. From there, it headed north to the Puget Sound area, where it has been ever since. The Navy’s investigation into the incident put heavy emphasis on how a weak command environment and lax attitudes toward the performance of key tasks had put the submarine on a path to the accident, as you can read more about in detail here.

The EDSRA formally began in February 2023. At that time, the Navy projected that the repairs would be completed in September 2025. By July 2023, the schedule had already shifted to early 2026, according to Naval News. In July 2025, the service confirmed to TWZ that the timeline had moved again to the right, to late 2026.

The exact reasons for the delays are unclear. TWZ has stressed the particular complexities of major repairs to any of the Navy’s trio of Seawolf class submarines in our past reporting on Connecticut. As we wrote in 2023 around the start of the EDSRA:

“As for the USS Connecticut, as the images show, her state remains relatively the same, at least in terms of what is visible, compared to when she arrived over a year and a half ago. Her sonar dome is still missing and, clearly, the boat has been idle for some time, with huge sections of its anechoic coating missing from its sail.”

“Major repairs to the submarine’s bow, sonar, and other underside structure components will be challenging as the Seawolf class is long out of production. On top of that, just three boats were ever built, with one being a heavily modified sub-type in its own right, the highly secretive USS Jimmy Carter (SSN-23). In the past, similar damage has been fixed by leveraging spare parts and entire sections of decommissioned submarines of the same class. That simply is not an option in this case.”

The Navy’s 2025 Fiscal Year budget proposal highlighted exactly these broader issues in seeking funds for spare bow domes “for use in the event replacement is required,” separate from the incident with the USS Connecticut. The original sustainment strategy for the Seawolf class did not include these items, which have a “three plus year lead time” to produce.

With the EDRSA, the Navy is also taking the opportunity to conduct a deep overhaul of USS Connecticut, which could include the integration of various upgrades. The Navy’s budget documents have long highlighted efforts to modernize key systems on all three Seawolf class submarines, some of which were first designed in the 1970s.

How much the repairs and accompanying overhaul will cost is also not clear. In 2021, Congress approved $40 million for “emergency repairs” for Connecticut and an additional $10 million for a new bow dome, but the full price tag is expected to be far steeper. The Seawolf class submarines were extremely expensive to procure in the first place, costing approximately $3.1 billion apiece in 1983, or some $10.6 billion in 2026 dollars. This was due in large part to the truncated order, from 29 down to three, as a result of post-Cold War drawdowns.

Depending on when repairs to the USS Connecticut are actually finished, the Navy could find itself for at least a time with just one Seawolf class submarine in active service. USS Seawolf is currently scheduled to start a routine maintenance availability next May, which will then run through February 2030, per Navy budget documents. As mentioned, the Navy is now also planning to inactivate USS Connecticut in 2031, making it the first Seawolf class submarine to be retired, per its most recent annual shipbuilding plan.

The service still has plans to acquire a new class of attack submarines, which has been discussed in the past as something closer to a true successor to the Seawolf class than the Virginia class boats being procured now. However, these new submarines, currently referred to as SSN(X), are not expected to arrive until the mid-2040s at the earliest. Between now and then, the Navy is set to acquire a one-of-a-kind seabed warfare version of the Virginia, which could well take over for the USS Jimmy Carter, as you can read more about here. In August, the service announced that stretched Block IV and V Virginia class submarines with Virginia Payload Modules (VPM) will now be categorized as guided-missile types (SSGN), as well.

When it comes to USS Connecticut, the Navy remains committed to getting the highly capable submarine back to the fleet after being sidelined for nearly five years now. At the same time, the boat has now already entered the twilight of its career, with just four years of active service life left if the current repair schedule holds.

Contact the author: joe@twz.com

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Japan has said it is keeping the door open to acquiring nuclear-powered submarines, a potentially major shift for a country whose submarine force has historically relied exclusively on conventional propulsion. Defense Minister Shinjiro Koizumi confirmed recently that Tokyo is not ruling out nuclear-powered submarines as it considers the future requirements of the Japan Maritime Self-Defense Force (JMSDF).

Should Japan ultimately pursue the capability, it would join an exclusive group of nations operating nuclear-powered submarines. China, France, India, Russia, the United Kingdom, and the United States are currently the only countries with nuclear-powered submarines in active service. Brazil is already working to join the club, while Australian and South Korean nuclear-powered submarine plans are somewhat longer-term.

Japan’s submarine fleet is already regarded as among the most capable conventionally powered forces, and is very much at the forefront of advanced naval propulsion technologies. Even with that considerable expertise, however, developing and sustaining a nuclear propulsion capability would represent a huge challenge, requiring expertise and infrastructure far beyond those needed to build Japan’s existing conventionally powered submarines.

Koizumi’s comments do not represent a decision to acquire nuclear-powered submarines, nor do they indicate that Japan has begun a procurement program. They do, however, mark a significant evolution in the country’s public debate over submarine propulsion and point to a growing willingness within the Japanese defense establishment to consider capabilities that were previously largely outside the mainstream of defense planning.

Currently, Japan operates one of the world’s most capable conventional submarine fleets, centered on increasingly sophisticated diesel-electric boats equipped with air-independent propulsion and advanced lithium-ion batteries. These submarines are well suited to operations around Japan and the country’s surrounding waters.

The JMSDF currently operates 22 conventionally powered submarines, maintaining the force structure established in the 2010s while progressively replacing older boats with the more capable Taigei class. Five Taigei class submarines are now in JMSDF service, with additional boats in the pipeline.

Nuclear propulsion, however, would offer substantially greater endurance and sustained underwater speed, allowing Japanese submarines to conduct longer-range operations across the broader Western Pacific with minimal support. This is a requirement that is becoming increasingly relevant as Tokyo’s strategic focus expands beyond its immediate maritime approaches.

China’s rapidly expanding naval force, including its growing submarine fleet and increasingly distant maritime operations, is forcing Tokyo to consider how it would monitor and potentially counter Chinese forces farther from the Japanese archipelago. A nuclear-powered attack submarine could remain submerged for extended periods without the endurance limitations imposed by conventional propulsion, making it particularly useful for long-range surveillance, tracking, and sea-denial missions.

Japan’s debate is also unfolding alongside a significant development in neighboring South Korea. Seoul has confirmed plans to develop a new class of nuclear-powered submarines, a move that could add further momentum to an emerging undersea competition in Northeast Asia. South Korea’s decision is particularly relevant to Tokyo because it demonstrates that nuclear propulsion is no longer merely a theoretical capability for U.S. allies in the region. While the missions and strategic priorities of the Japanese and South Korean navies are different, both countries face the challenge of operating in waters increasingly contested by China and North Korea.

The development could also create new opportunities for Japan to work more closely with Australia and the other AUKUS partners. Australia is in the process of acquiring its own conventionally armed, nuclear-powered submarine capability under AUKUS Pillar I, with U.S. and U.K. nuclear-powered submarines also scheduled to operate from Australia. Japan has separately been identified as a potential partner for AUKUS Pillar II, which covers advanced capabilities and technology cooperation.

A Japanese decision to pursue SSNs could eventually create a much deeper basis for cooperation with Australia, including submarine interoperability, undersea warfare, workforce and technical expertise, infrastructure, sustainment, and potentially aspects of the industrial base. Analysts have already examined how Japan could fit into the wider AUKUS submarine ecosystem as Australia’s nuclear-submarine program develops.

A Japanese nuclear-powered submarine with a robust capacity to launch land attack cruise missiles would also be a powerful component in the country’s emerging “counterstrike” posture, which is increasingly centered on acquiring the ability to strike targets at longer ranges.

Japan has already begun deploying domestically developed long-range missile systems, including the Upgraded Type 12 surface-to-ship missile, while also acquiring the U.S.-made Tomahawk cruise missile.

An SSN would potentially add a highly survivable, mobile platform to this emerging strike architecture, allowing Japan to position long-range weapons farther from its home territory and complicating an adversary’s efforts to locate and neutralize them. That could be particularly valuable in a conflict in which Japanese air bases, missile batteries, and other fixed infrastructure were under attack.

The potential SSN requirement also fits with Japan’s expanding expeditionary ambitions. As the JMSDF converts its Izumo class helicopter destroyers to operate F-35B fighters, giving Japan a more credible carrier aviation capability, nuclear-powered attack submarines could provide a valuable escort for these increasingly important surface groups. Their speed, endurance, and ability to remain submerged for extended periods makes SSNs particularly well suited to accompanying carrier forces on longer-range deployments and supporting contingencies farther from Japanese waters.

Looking at the bigger picture, it is highly significant that nuclear propulsion was effectively excluded from Japan’s conventional defense debate for decades. More recently, however, Japanese defense officials and policymakers have begun examining whether future submarines will require a different propulsion system. The issue is now one that can be discussed openly at the ministerial level.

Nevertheless, pursuing a nuclear-powered submarine program would come with huge challenges.

Building and operating nuclear-powered submarines would require Japan to establish an entirely different industrial, regulatory, and training infrastructure. The vessels would also be considerably more expensive and complex to build and operate than Japan’s existing conventionally powered submarines. Tokyo would have to resolve questions involving nuclear regulation, reactor technology, maintenance facilities, crew training, and the handling of nuclear material.

There would also be a significant political dimension. Although naval nuclear propulsion is fundamentally different from possessing nuclear weapons, any move in that direction would inevitably receive scrutiny in a country whose postwar security policy has been shaped by its experience with nuclear weapons and its longstanding non-nuclear principles.

For those reasons, Koizumi’s statement should be viewed less as an announcement of a Japanese nuclear-submarine program than as evidence that the political barrier to discussing such a program is falling.

The next question is whether the Japanese government will move from keeping the option open to actually studying a nuclear-powered submarine design, propulsion technology, and acquisition pathway in detail.

If it does, the consequences could extend well beyond Japan’s submarine fleet. A Japanese nuclear-powered submarine capability would represent a major enhancement of Tokyo’s ability to operate across the Western Pacific and could alter the undersea balance between Japan, China, and the United States’ other regional allies. At the very least, the idea is one that is now part of wider discussions at the highest levels.

Contact the author: thomas@thewarzone.com

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