Japan Launches Seventh Taigei-Class Submarine

Mitsubishi Heavy Industries has launched the seventh Taigei-class submarine for the Japan Maritime Self-Defense Force.

This was reported by the company’s press office.

The christening and launching ceremony took place on October 8, 2026, at the Mitsubishi Heavy Industries shipyard in Kobe.

The submarine was named Sōgei (しょうげい) and assigned the hull number SS-519.

Construction of SS-519 began on April 17, 2024. Following the launch, work will continue on the submarine to install hull equipment, the power plant, electronic systems, and weapons.

It is scheduled to be delivered to the Japanese Ministry of Defense during fiscal year 2027, that is, by March 2028.

Taigei-class submarines are characterized by enhanced target detection capabilities and reduced noise levels compared to the previous Sōryū-class.

Representatives from Mitsubishi Heavy Industries also note that the new submarines feature an improved hull design and more advanced hydroacoustic equipment.

Furthermore, unlike some of the previous Sōryū-class submarines, the Taigei is not equipped with a separate air-independent propulsion system. Japan has abandoned the Stirling AIP system in favor of powerful lithium-ion batteries. The last submarine of this class, named Sōgei, was launched on October 15, 2025.

While submerged, the submarine uses electricity stored in its batteries, and recharges them using diesel engines while operating on surface. Lithium-ion batteries have a higher energy density compared to traditional lead-acid batteries, giving the Taigei a longer underwater endurance and better capabilities for rapid maneuvering.

Eliminating a separate AIP system also simplified the propulsion system and allowed the freed-up weight and volume to be used for other submarine systems.

Specifications:

Displacement: approximately 3,000 metric tons.
Length: 84 m.
Beam: 9.1 m.
Crew: approximately 70 personnel.
Propulsion system: diesel-electric, single-shaft.
Power: approximately 6,000 k.s.
Maximum speed: 20 knots – submerged.

Armament:

Torpedo armament: six 533 mm torpedo tubes.
Main armament: Type 18 torpedoes, Harpoon anti-ship missiles, and other weapons launched through torpedo tubes.