Sōryū-class submarine. The Sōryū-class submarines (16SS) are diesel-electric attack submarines. The first boat in the class entered service with the Japan Maritime Self-Defense Force in 2009. The design is an evolution of the , from which it can most easily be distinguished by its X-shaped stern combination diving planes and rudders. At the time of launching, the Sōryūs had the largest displacement of any submarine used by post-war Japan.

The Sōryū-class is Japan's first air-independent propulsion submarine class. From Sōryū to Shōryū are fitted with Kockums Naval Solutions Stirling engines license-built by Kawasaki Heavy Industries, allowing them to stay submerged for longer periods of time. The 11th submarine of the class, Ōryū, is the world's first lithium-ion battery submarine. The cost of the sixth submarine (Kokuryū) was estimated at US$540 million.

In 2023, the first of the replacements for the Sōryūs, the Taigei-class submarine, entered service.

Naming convention
Japanese submarines since World War II were named after ocean currents. The JMSDF changed its naming convention with the Sōryū, and submarines will now be named after mythological creatures. Sōryū (そうりゅう) means blue dragon in Japanese and shares its name with the World War II aircraft carrier , sunk during the Battle of Midway.

Variants

The eleventh Sōryū-class submarine (Ōryū) is the first Japanese submarine in the fleet to mount lithium-ion batteries. The JS Ōryū was given a budget of  under the 2015 Japanese Defense Budget.

Lithium-ion batteries have almost twice the electric storage capacity of traditional lead-acid batteries. Updated Sōryū-class boats also added more batteries by placing them within hull spaces previously occupied by AIP system machinery. These upgraded boats benefited by increasing both the size and energy density of their battery storage. The change to lithium-ion improved the underwater endurance significantly and will be an advantage over the slow recharge capability of the AIP system.

In any event, JMSDF believes that lithium-ion is the way forward and intends to 'trial' this new system and compare it to the previous AIP system for operational effectiveness.

Exports
Japan offered Sōryū-class submarines to Australia as replacements for the Royal Australian Navy's s, as part of the . On 9 April 2014, then-Australian Minister for Defence, David Johnston, described the Sōryū class as "extremely impressive" while discussing Australia's future submarine options. On 26 April 2016, Australian Prime Minister Malcolm Turnbull announced that the Australian contract had been awarded to the French-designed Shortfin Barracuda, though this deal was eventually rescinded.

India, Morocco, Norway, Netherlands, and Taiwan have also approached Japan, and expressed an interest in buying Sōryū-class submarines. During a visit to Japan, India's then-Union Minister of Defence, Manohar Parrikar, invited the Japanese government to participate in their US$8.1 billion Project 75I-class submarine procurement program.

Boats

See also
 List of submarine classes in service

 Submarines of similar comparison
 Blekinge-class submarine—A class of submarine developed by Kockums for the Swedish Navy
 Type 218SG submarine—A class of extensively-customised diesel-electric attack submarines developed by ThyssenKrupp Marine Systems and currently operated by the Republic of Singapore Navy
 —A unique class of diesel-electric attack submarines developed by ThyssenKrupp Marine Systems and currently being built for Israel
 —A class of extensively-customised diesel-electric attack submarines developed by ThyssenKrupp Marine Systems and currently operated by Israel
 —A class of diesel-electric attack submarines currently being built by CSBC for Taiwan
 KSS-III submarine—A class of diesel-electric attack and ballistic missile submarines, built by Hanwha Ocean and HD Hyundai Heavy Industries and operated by the Republic of Korea Navy
 —A class of diesel-electric attack submarines being built for the Russian Navy
 S-80 Plus submarine—A class of conventionally-powered attack submarines, currently being built by Navantia for the Spanish Navy
 —A class of export-oriented diesel-electric attack submarines, jointly developed by Naval Group and Navantia and currently operated by the Chilean Navy, the Royal Malaysian Navy, the Indian Navy and the Brazilian Navy
 —A class of diesel-electric attack submarines currently being built by Mitsubishi Heavy Industries and Kawasaki Heavy Industries for the Japan Maritime Self-Defense Force
 Type 039A submarine—A class of diesel-electric attack submarines operated by the People's Liberation Army Navy (China) and being built for the Royal Thai Navy and the Pakistan Navy
 Type 212 submarine—A class of diesel-electric attack submarines developed by ThyssenKrupp Marine Systems and exclusively built for the German Navy, the Italian Navy and the Royal Norwegian Navy
 Type 214 submarine—A class of export-oriented diesel-electric attack submarines, developed by ThyssenKrupp Marine Systems and currently operated by the Hellenic Navy, the Portuguese Navy, the Republic of Korea Navy and the Turkish Naval Forces

References

External links

Japanese website with Diagram
Globalsecurity.org
Military-today.com
Soryu Class 16SS SSK Submarine - Japan Maritime Self-Defense Force on navyrecognition.com

Website on the Imperial Japanese Navy: JMSDF vessels
SWZmaritime December 2020, Japan special

Submarine classes
 
 
Mitsubishi Heavy Industries submarines