{"id":38208,"date":"2026-10-12T09:59:08","date_gmt":"2026-10-12T06:59:08","guid":{"rendered":"https:\/\/www.ir-ia.com\/news\/?p=38208"},"modified":"2026-10-12T09:59:12","modified_gmt":"2026-10-12T06:59:12","slug":"japan-launches-seventh-taigei-class-submarine-to-strengthen-undersea-warfare-capabilities","status":"publish","type":"post","link":"https:\/\/www.ir-ia.com\/news\/japan-launches-seventh-taigei-class-submarine-to-strengthen-undersea-warfare-capabilities\/","title":{"rendered":"Japan launches seventh Taigei-class submarine to strengthen undersea warfare capabilities"},"content":{"rendered":"\n

5 minute read<\/em><\/p>\n\n\n\n

Japan\u2019s Mitsubishi Heavy Industries (MHI) launched the seventh Taigei-class diesel-electric attack submarine, Shogei (SS-519), at its shipyard in Kobe, Hyogo Prefecture.<\/strong><\/p>\n\n\n\n

The 3,000-tonne submarine is scheduled for delivery to the Japan Maritime Self-Defense Force (JMSDF) by March 2028, as Tokyo continues developing its submarine capabilities and considers propulsion options for future vessels, including nuclear power.<\/p>\n\n\n\n

Shogei (SS-519) submarine measures 84 meters in length and 9.1 meters in beam, with a standard displacement of approximately 3,000 tonnes. Its construction cost is reported at 80.5 billion yen, or about $509 million.<\/p>\n\n\n\n

The submarine is the seventh vessel in the Taigei class, which is replacing the older Soryu class as a central component of Japan\u2019s conventional submarine fleet. MHI and Kawasaki Heavy Industries, both based in Kobe, alternate construction of the class.<\/p>\n\n\n\n

The lead submarine, Taigei, entered service in March 2022 and has since been reassigned as a test submarine. The sixth vessel, Sogei, launched in October 2025, is scheduled to enter service in March 2027. Shogei is expected to follow after completing outfitting and sea trials.<\/p>\n\n\n\n

The newer Taigei-class submarines use more powerful Kawasaki 12V 25\/31 diesel engines. The class is designed around large-capacity lithium-ion batteries, which provide greater underwater endurance than conventional lead-acid batteries. Japan previously introduced lithium-ion batteries on the final two Soryu-class submarines, Oryu and Toryu.<\/p>\n\n\n\n

Unlike earlier Soryu-class vessels, which use a Stirling air-independent propulsion system, the Taigei class relies on its battery system for underwater operations. Its design also incorporates improved sonar and measures to reduce noise, helping limit the submarine\u2019s acoustic signature.<\/p>\n\n\n\n

The submarine can accommodate approximately 40 personnel, with dedicated living quarters for female crew members. Its reported maximum speed is around 20 knots.<\/p>\n\n\n

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\"Japan's<\/a>
Japan’s Taigei-class submarine test. (Image Credit: JMSDF)<\/sup><\/em>

<\/figcaption><\/figure>\n<\/div>\n\n\n


Weapons and Operational Capabilities<\/strong><\/p>\n\n\n\n

The Taigei class is equipped to conduct anti-submarine and anti-surface warfare. Its weapons include Japan\u2019s Type 18 heavyweight torpedo, which succeeds the Type 89 and incorporates improvements in propulsion, target detection, and processing.<\/p>\n\n\n\n

The submarines can also launch UGM-84L Harpoon Block II anti-ship missiles against surface targets. The missile has a reported range of approximately 248 kilometers.<\/p>\n\n\n\n

Japan is also pursuing submarines equipped with vertical launching systems (VLS) capable of firing long-range stand-off missiles. Such systems would expand the fleet\u2019s strike options but could require significant changes to submarine design, including a larger hull and additional space for launch equipment.<\/p>\n\n\n\n

MHI has said it will continue working to reduce crew requirements, improve cybersecurity and lower life-cycle costs. The company has also indicated that it is exploring a new submarine design beyond the current approach, although it has not disclosed further details.<\/p>\n\n\n\n


Japan\u2019s Next-Generation Submarine Design<\/strong><\/p>\n\n\n\n

Japan\u2019s submarine modernization is taking place as the Chinese Navy expands its activities across the Western Pacific. Tokyo increasingly values the ability to deploy submarines over long distances, remain submerged for extended periods, and carry out missions while reducing the risk of detection.<\/p>\n\n\n\n

Under the three national security documents adopted in December 2022, Japan\u2019s Ministry of Defense is pursuing the development and eventual acquisition of VLS-equipped submarines.<\/p>\n\n\n\n

On July 6, 2026, Japan\u2019s Acquisition, Technology & Logistics Agency awarded MHI a 3.9 billion yen contract, worth approximately $24.6 million, for research into the overall design optimization of a next-generation submarine equipped with vertical launch systems. The research is scheduled to run from fiscal 2026 through fiscal 2029.<\/p>\n\n\n

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\"Japan's<\/a>
Japan’s seventh Taigei-class submarine \u201cShogei\u201d. (Image Credit: Mitsubishi Heavy Industries)<\/sup><\/em><\/figcaption><\/figure>\n<\/div>\n\n\n

Integrating VLS could increase the vessel\u2019s size and complexity. More advanced sonar, additional onboard systems, and the use of unmanned underwater vehicles could also raise power requirements, creating further challenges for conventionally powered submarines.<\/p>\n\n\n\n

In September 2025, an expert panel advising the Ministry of Defense recommended further research and technological development for VLS-equipped submarines, including consideration of what it described as \u201cnext-generation propulsion.\u201d The recommendation did not explicitly call for nuclear propulsion.<\/p>\n\n\n\n


Nuclear Power Remains an Option<\/strong><\/p>\n\n\n\n

Japan is also examining whether nuclear propulsion could meet the demands of its future submarine force. Conventional diesel-electric submarines must periodically operate their diesel engines to recharge their batteries. To do so while submerged, they generally need to rise to snorkel depth to draw in air and discharge exhaust, increasing their risk of detection.<\/p>\n\n\n\n

Lithium-ion batteries allow the Taigei class to remain underwater longer, but they still have finite energy reserves. Sustained high-speed operations consume energy rapidly, limiting the ability of conventional submarines to combine high speed, long-distance transit and prolonged submerged operations.<\/p>\n\n\n\n

Nuclear-powered submarines can operate underwater for extended periods without surfacing or snorkeling to recharge batteries. They can also maintain high speeds for longer, potentially improving operational flexibility and allowing crews to respond more effectively to threats, including enemy anti-submarine warfare operations.<\/p>\n\n\n\n

On September 11, 2026, Japanese Defense Minister Shinjiro Koizumi said Tokyo would not rule out nuclear-powered submarines as it considers revisions to its three national security documents by the end of the year. He highlighted their endurance and speed, while noting that the technology also presents significant disadvantages.<\/p>\n\n\n\n

These include higher acquisition and operating costs, larger hull requirements, the need for specialized personnel and maintenance infrastructure, and the possibility of greater underwater acoustic signatures. Japan would also need to address nuclear safety, crew training, and the long-term management of naval reactors.<\/p>\n\n\n

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\"Japan's<\/a>
Japan Maritime Self-Defense Force Taigei-class submarine. (Image Credit: JMSDF)<\/sup><\/em><\/figcaption><\/figure>\n<\/div>\n\n\n

Japan has not decided to acquire nuclear-powered submarines. Its future choices will depend on the missions required of the fleet, the capabilities needed to carry them out, and the costs, technical challenges, and safety requirements associated with each propulsion system.<\/p>\n","protected":false},"excerpt":{"rendered":"

Japan\u2019s Mitsubishi Heavy Industries (MHI) launched the seventh Taigei-class diesel-electric attack submarine, Shogei (SS-519), at its shipyard in Kobe, Hyogo Prefecture.<\/p>\n","protected":false},"author":1,"featured_media":38213,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_feature_clip_id":0,"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":true,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2},"jetpack_post_was_ever_published":false},"categories":[124,1],"tags":[137,380,6,46,184,860,90,108,287,63],"class_list":["post-38208","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-asia-pacific","category-news","tag-asia","tag-asia-pacific","tag-defense","tag-japan","tag-maritime","tag-mitsubishi","tag-navy","tag-nuclear","tag-submarine","tag-weapons"],"jetpack_publicize_connections":[],"jetpack_shortlink":"https:\/\/wp.me\/p7jJWb-9Wg","jetpack_sharing_enabled":true,"jetpack_featured_media_url":"https:\/\/i0.wp.com\/www.ir-ia.com\/news\/wp-content\/uploads\/2026\/10\/Japan-Taigei-class-submarine.jpg?fit=690%2C370&ssl=1","_links":{"self":[{"href":"https:\/\/www.ir-ia.com\/news\/wp-json\/wp\/v2\/posts\/38208","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.ir-ia.com\/news\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.ir-ia.com\/news\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.ir-ia.com\/news\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.ir-ia.com\/news\/wp-json\/wp\/v2\/comments?post=38208"}],"version-history":[{"count":1,"href":"https:\/\/www.ir-ia.com\/news\/wp-json\/wp\/v2\/posts\/38208\/revisions"}],"predecessor-version":[{"id":38216,"href":"https:\/\/www.ir-ia.com\/news\/wp-json\/wp\/v2\/posts\/38208\/revisions\/38216"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.ir-ia.com\/news\/wp-json\/wp\/v2\/media\/38213"}],"wp:attachment":[{"href":"https:\/\/www.ir-ia.com\/news\/wp-json\/wp\/v2\/media?parent=38208"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.ir-ia.com\/news\/wp-json\/wp\/v2\/categories?post=38208"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.ir-ia.com\/news\/wp-json\/wp\/v2\/tags?post=38208"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}