As part of ongoing bilateral cooperation since the 2010s, Russia has transferred technical documentation and materials for submarine testing to China, boosting the tactical advantages of Beijing’s growing undersea fleet. This technological exchange has continued even after the start of Russia’s full-scale invasion of Ukraine in February 2022, according to a report titled “A Marriage of Convenience?” published by the research organization Center for Advanced Defense Studies (C4ADS).
Historical Naval Exchanges and Russian Engineering Support
China’s submarine fleet, particularly its non-nuclear component, initially relied on Soviet and Russian technologies before the Chinese Navy transitioned to domestically produced platforms. According to experts cited in the C4ADS report, Sino-Russian cooperation encompasses noise-reduction technologies, non-nuclear propulsion systems, automated command, control, and weapon management systems, as well as submarine hull design.
U.S. government sources claim that China’s nuclear submarine program continues to receive significant Russian technical assistance, particularly in the area of reducing acoustic signatures. Analysts also believe that China obtained technological assistance from Russia to quiet its submarines in exchange for its assistance during the Russo-Ukrainian war.
Rubin Bureau Deliveries and Joint Testing
The Russian Central Design Bureau for Marine Engineering Rubin, a subsidiary of the state-owned United Shipbuilding Corporation (USC), plays a key role in the cooperation between the two countries and is subject to sanctions imposed by the United States, the European Union, and Japan. Trade data confirms that from at least August 2015 through April 2023, Rubin collaborated with procurement agencies of the People’s Liberation Army of China and China Shipbuilding and Offshore International Co., Ltd. (CSOC) on the joint development of submarine technologies. CSOC operates as the foreign trade division of the China State Shipbuilding Corporation, which builds civilian and military vessels.
During this period, Rubin made 12 deliveries to the PLA Navy procurement agencies and CSOC with a total value of over $80 million. According to the report’s authors, the vague descriptions of these deliveries likely pertain to conceptual designs for a non-nuclear submarine. In particular, two deliveries from Rubin to CSOC in October 2019 and January 2020 included documentation regarding various submarine-related tests, including tests to evaluate cavitation, a natural phenomenon that impairs the stealth capabilities of submarines. According to a maritime security expert consulted by the report’s authors, these details indicate that Rubin helped CSOC test the effectiveness of Chinese technologies for reducing submarine noise. Available data also indicates that from December 2019 to September 2022, CSOC supplied Rubin with materials for submarine testing, including control devices and components for test consoles used to evaluate the submarine’s information and control system, while documents related to a shipment in September 2022 also mention a contract for joint design and production.
Operational Impact on the PLA Navy Submarine Force
The People’s Liberation Army Navy Submarine Force currently operates a fleet of 66 submarines including nuclear as well as conventional platforms organized into three fleets: the North Sea Fleet, the East Sea Fleet, and the South Sea Fleet. Submarines have long been one of the three main focuses of the People’s Liberation Army Navy alongside aircraft and major surface combatants. The nuclear component includes the Type 094 ballistic missile submarine, which is believed to have been influenced by Russian assistance and features 12 launch tubes for the longer-ranged JL-2 missile with an 8,000-kilometer range capable of carrying three to four independently targetable reentry vehicles.
In the conventional domain, engineering modifications have improved the capabilities of the PLA Navy’s Yuan-class platforms. Writing in the March 2026 issue of the PRC navalist publication *Shipborne Weapons*, author Yin He detailed engineering modifications that improved the Type 039B over the Type 039A, including advances in propulsion, acoustic quieting, and overall performance. The Type 039B features the Yu-6 torpedo combining anti-submarine warfare and anti-surface warfare capabilities, the long-range YJ-18 anti-ship cruise missile derived from Russia’s Club-S submarine-launched system but substantially redesigned to meet Chinese requirements, and a next-generation integrated sonar and combat-command suite including large passive flank arrays.
Strategic Implications for Future Submarine Development
The technical assistance from Moscow directly impacts how Beijing develops platforms for near-seas operations and future warfare. Yin He described China’s small-step, fast-iteration approach to submarine development, noting that changes to the Type 039C include a distinctive axe-shaped sail, an X-shaped rudder, and composite materials intended to improve stealth and maneuverability. The author assesses that the Type 039C may serve as a test platform for new designs, equipment, propulsion technologies, and weapons systems.
Looking forward, the analysis indicates that the People’s Liberation Army Navy will still require a fleet of conventional submarines for operations in the near seas, which may eventually operate on lithium-ion batteries as an evolutionary change. Future all-electric submarines would require solid-state batteries as well as integrated electric-propulsion systems, medium-voltage DC power-distribution systems, and supercapacitor energy-storage systems, representing a generational shift. As technical documentation and materials continue to pass between Russian design bureaus and Chinese procurement agencies, these engineering integrations shape the acoustic profile and operational reach of the entire fleet.
Historical Background of Sino-Russian Naval Cooperation
The foundation of China’s submarine fleet, particularly its non-nuclear component, was built upon Soviet and Russian technologies. While the Chinese Navy has since transitioned toward domestically produced platforms, this early reliance established a long-standing framework for bilateral technical engagement. According to experts cited in the C4ADS report, this cooperation has historically encompassed a broad range of critical naval disciplines, including submarine hull design, noise-reduction technologies, non-nuclear propulsion systems, and automated command, control, and weapon management systems.
This collaborative relationship has persisted through various stages of China’s naval modernization. Beyond the initial transfer of foundational systems, the partnership evolved into a sustained exchange of technical documentation and materials for submarine testing. This trend of technological assistance has continued throughout the 2010s and remains active even following the start of Russia’s full-scale invasion of Ukraine in February 2022, underscoring the enduring nature of the naval engineering ties between Moscow and Beijing.
Sources
- Russia Transferred Non-Nuclear Submarine Technology to China
- People's Liberation Army Navy Submarine Force
- Andrew S. Erickson
Photo: Chairman of the Joint Chiefs of Staff from Washington D.C, United States (CC BY 2.0)
