The Japan Maritime Self-Defense Force (JMSDF) has officially commissioned its fourth Taigei-class diesel-electric attack submarine, the JS Raigei (SS 516).
Equipped with advanced detection and anti-detection capabilities, the submarine was delivered by Kawasaki Heavy Industries (KHI) on March 6, 2025, and incorporated into the 1st Submarine Division of the 1st Submarine Flotilla, stationed at the Kure Naval Base in Hiroshima Prefecture.
JS Raigei Characteristics
According to Naval News, the JS Raigei measures 84 meters in length, with a beam of 9.1 meters and a draft of 10.4 meters, displacing approximately 3,000 tons. Compared to the Soryu-class submarines, the Raigei is slightly larger and introduces an unprecedented advancement in the JMSDF fleet: dedicated compartments for up to six women, reflecting greater inclusivity in Japan’s submarine service.
Named after the “thunder whale,” the Raigei is powered by a diesel-electric engine generating 6,000 horsepower, enabling a maximum submerged speed of 20 knots. It features the ZQQ-8 sonar system, an upgrade from the Soryu-class ZQQ-7, providing enhanced underwater detection capabilities.
The Raigei is the first Taigei-class submarine to be equipped with the new Kawasaki 12V 25/31 diesel engines, increasing power and ensuring compatibility with a new snorkel system. Another innovation is the use of lithium-ion batteries, manufactured by GS Yuasa, replacing traditional lead-acid batteries and establishing Japan as a pioneer in integrating this technology into conventional submarines (SSKs).
Systems and Armament
The submarine incorporates an upgraded combat management system (CMS), integrating advanced sensors, command and control, and weapon engagement systems. It is also equipped with a fiber-optic array sonar system, a non-penetrating periscope, and a countermeasure system.
In terms of weaponry, the Raigei can launch Type 18 torpedoes and UGM-84L Harpoon Block II anti-ship missiles, with a range of 248 km, extending Japan’s offensive capabilities. The commissioning of the Taigei-class submarines is seen as a strategic response to the growing Chinese naval presence, particularly with the upcoming deployment of China’s third aircraft carrier, the Fujian, which is expected to increase operations in the Western Pacific.
Fleet Expansion
The JS Raigei joins the Taigei (SS 513), Hakugei (SS 514), and Jingei (SS 515) submarines. The fifth vessel in the class, Chogei, was launched in October 2024 and is scheduled to enter service in March 2026. With this, the JMSDF continues to expand its fleet, strengthening its strategic position in the Indo-Pacific region.
Source and images: X @JMSDF_PAO. This content was created with AI assistance and reviewed by the editorial team.
