For years, China has supplied Russia with the industrial components, electronics, and dual use technology that have helped Moscow sustain its war in Ukraine. Now the relationship is flowing in the opposite direction. According to multiple defense analysts and recent reporting, Russia is providing China with advanced military technology, operational experience, training, and intelligence that could significantly strengthen China’s armed forces. Together, these exchanges are creating a military partnership that is becoming one of the defining strategic developments of the decade.

The Economist recently reported that Western officials are increasingly concerned that China is receiving “training, intelligence and advanced military technology from Russia.” It noted that this growing flow of knowledge could give China an important advantage in any future conflict over Taiwan while shifting the balance of power across the Indo-Pacific.c

As advanced as China is in many of its technologies, Russia’s defense industry and combat experience surpass the Chinese in ways that count.

Submarine Technology May Be the Biggest Prize

Among the most valuable technologies China seeks from Russia is submarine expertise. Although China has built one of the world’s largest navies, its submarine fleet still trails Russia and the United States in several critical areas, including quieting technology, hull design, automation, advanced sensors, and underwater stealth.

Admiral Samuel Paparo, commander of U.S. Indo-Pacific Command, warned that Russia could “provide submarine technology to the PRC that has the potential of closing American undersea dominance.” Analysts note that Russian nuclear submarines, particularly the Yasen class, represent decades of accumulated engineering expertise that China has struggled to duplicate on its own.

Should Russia transfer enough of this knowledge, China could rapidly improve both its conventional and nuclear submarine fleets. Combined with China’s massive shipbuilding capacity, Russian designs could eventually be produced at a scale that neither Russia nor the West could easily match.

Air Defense and Combat Aircraft

Russia has already supplied China with some of its most capable military hardware. Major agreements signed after 2015 included deliveries of Su-35 fighter aircraft and S-400 long range air defense systems valued at roughly $5 billion. These systems represented a major departure from Russia’s earlier reluctance to export its most advanced military equipment to China.

The Su-35 provides China access to advanced radar systems, avionics, thrust vectoring engines, and other technologies that help bridge gaps in China’s own fighter development. Meanwhile, the S-400 dramatically extends China’s long range air defense network and strengthens its ability to defend critical military infrastructure and contested areas in the East and South China Seas.

Beyond complete weapons systems, Russia continues supplying aircraft engines that remain difficult for China to manufacture independently. These engines support fighters, bombers, and transport aircraft while giving Chinese engineers opportunities to study technologies that remain among the most difficult to reverse engineer.

Drones, Battlefield Experience, and Military Know How

The partnership extends well beyond hardware.

Russia’s war in Ukraine has produced an enormous amount of operational experience in drone warfare, electronic warfare, air defense, missile operations, and battlefield adaptation. According to The Economist, China is benefiting from Russian training and intelligence derived from these combat experiences. Those lessons are especially valuable because they come from one of the largest conventional wars fought in decades.

China has supplied Russia with engines, electronics, semiconductors, machine tools, and other dual use components that help sustain Russia’s defense industry. In return, analysts believe Russia is increasingly willing to provide military expertise that Beijing had previously been unable to obtain.

The relationship has become increasingly transactional, with each nation supplying capabilities the other lacks.

Beyond Weapons Systems

Military cooperation now reaches well beyond traditional arms sales.

Researchers describe expanding cooperation in missile early warning systems, artificial intelligence, space technologies, helicopters, naval systems, and joint development programs. Russia and China have also increased combined military exercises, joint air patrols, missile defense activities, and regular engagements between senior military leaders.

One of the most strategically important projects is cooperation on ballistic missile early warning systems. Such systems could significantly improve China’s strategic nuclear posture by providing earlier warning of incoming missile attacks and strengthening its overall deterrence capabilities. Analysts also point to expanding cooperation in heavy lift helicopters and advanced submarine development as projects that could reshape China’s military capabilities over the next decade.

Why Russia Is Helping China

Russia’s motivations are rooted in both economics and geopolitics.

Following the invasion of Ukraine, Western sanctions sharply reduced Russia’s access to international markets and advanced technology. China became Moscow’s most important economic partner, providing critical trade, industrial production, electronics, and dual use components that helped sustain Russia’s defense industry. According to the Center for Naval Analyses, Moscow accepted greater risks by relaxing long standing restrictions on technology transfers in order to strengthen its strategic partnership with Beijing and offset Western pressure.

China also remains one of Russia’s largest arms customers, while offering access to manufacturing capacity and commercial technologies that Russia increasingly needs.

The Alliance Still Has Limits

Despite the growing partnership, Russia continues to exercise caution.

Russian officials remain concerned about Chinese reverse engineering and intellectual property theft. According to one report, Russian officials have documented hundreds of cases involving unauthorized copying of Russian technology. As a result, Moscow still withholds some of its most sensitive military capabilities, including technologies such as the RD-180 rocket engine, while reportedly declining to export systems like the Iskander missile.

Russia also continues exporting modified versions of many advanced weapons while reserving its newest capabilities for its own armed forces. Even so, analysts conclude that the overall trend continues toward greater technology sharing than at any previous point in the modern relationship.

A Broader Authoritarian Network

Russia’s military cooperation extends beyond China.

CSIS researchers describe expanding military technical relationships among Russia, China, Iran, and North Korea. China provides industrial capacity and dual use technology. Iran supplies drones and missiles while gaining access to advanced Russian aircraft and radar systems. North Korea contributes artillery ammunition and missiles while seeking assistance with satellite, missile, and nuclear related technologies. Each country supplies capabilities that strengthen the others while reducing the impact of Western sanctions.

Admiral Paparo described this growing relationship as a “transactional symbiosis,” explaining that “where one is resource poor, the others fulfill those resources. Where one has operational needs, the others are fulfilling those needs.”

A Partnership That Multiplies Power

Taken together, the evidence suggests Russia and China are building far more than a traditional arms trading relationship. Russia contributes decades of military research, combat experience, and specialized engineering expertise. China contributes manufacturing capacity, industrial scale, economic support, and the ability to rapidly absorb and expand upon imported technologies.

The result is a partnership that magnifies the strengths of both nations. Russia gains the economic and industrial support needed to sustain its military capabilities under sanctions, while China accelerates its military modernization by acquiring technologies that would otherwise take many years to develop independently. Analysts caution that this convergence has the potential to reshape the military balance across the Indo-Pacific, making the growing Russia-China military partnership one of the most consequential strategic developments facing the West today.