Japan to Launch New Taigei-Class Submarine SS-518 at Kobe Shipyard on October 14

Japan’s Maritime Staff Office (MSO) announced that the naming and launching ceremony for the fiscal year 2022 submarine will take place on 14 October 2025 at Kawasaki Heavy Industries’ Kobe Shipyard. The submarine is expected to be SS-518, part of the Taigei-class series operated by the Japan Maritime Self-Defense Force (JMSDF). The launch continues Japan’s program to modernize its diesel-electric submarine fleet using lithium-ion battery technology.

The Taigei-class is the latest generation of Japanese conventional submarines, developed after the Sōryū-class. These submarines are designed for longer underwater operation, with reduced need to surface or use snorkels. The use of lithium-ion batteries provides faster recharging, higher underwater speed, and quieter performance compared to older models.

Kawasaki Heavy Industries and Mitsubishi Heavy Industries share responsibility for building these submarines. The launch of SS-518 adds another lithium-ion battery-powered submarine to the JMSDF fleet, following the lead boat JS Taigei (SS-513), commissioned in 2022.

The Taigei-class has a displacement of about 3,000 tons, a length of approximately 84 meters, beam of 9.1 meters, and draught of 10.4 meters. It carries about 70 crew members and uses a diesel-electric propulsion system with large-capacity lithium-ion batteries. The submarine can reach submerged speeds of around 20 knots.

The submarine is armed with six 533 mm torpedo tubes capable of launching Type 18 heavy torpedoes and UGM-84 Harpoon anti-ship missiles. It includes design improvements such as a “floating floor” structure and sound-absorbing coatings to reduce noise. The sonar system, identified as the ZQQ-8, offers improved detection of surface and underwater targets.

The submarine has an “X”-shaped stern rudder for better maneuvering in coastal waters and an updated combat management system for coordination with other JMSDF assets.

The addition of SS-518 will strengthen Japan’s submarine operations, particularly in monitoring nearby waters where Chinese and Russian naval activities are common. The Taigei-class emphasizes longer underwater endurance, reduced detection risk, and improved operational reliability for Japan’s undersea fleet.