China and Russia quietly marked a new milestone this summer: their first joint submarine patrol. On the surface, it looked modest — just two Kilo-class diesel-electric subs, one Russian, one Chinese, accompanied by a corvette and support vessel. But symbolically, it signaled something deeper: Moscow and Beijing are increasingly willing to project themselves as a coordinated maritime force, even beneath the waves.
For Washington and its allies, the question is less about immediate firepower than about intent. “This is deterrence by impression,” said Lyle Goldstein, director of the Asia Program at Defense Priorities. “Neither side expects to fight the West together tomorrow. But they do want the U.S. to imagine that possibility.”
The symbolism mattered. Kilo-class submarines, though aging Soviet designs, represent a rare common platform: China imported the type from Russia in the 1990s, making interoperability relatively easy. What both navies chose not to do is telling — there was no cooperation with nuclear-powered submarines, the crown jewels of both fleets. Analysts say neither side wants to expose its most advanced technologies to a “partner” that could one day be a rival.
That restraint underscores the peculiar nature of the Sino-Russian embrace. It is tactical rather than fraternal, rooted in shared hostility to Washington rather than shared trust. The two powers have a bloody history of border clashes, and Moscow still fears Beijing’s designs on the sparsely populated Russian Far East. “They’re working together, but it’s not NATO-level integration,” observed Richard Moss of the U.S. Naval War College.
Yet the pattern is clear. Joint bomber patrols began in 2019, surface ship patrols in 2021, land exercises under the Zapad/Interaction brand the same year. The undersea domain is simply the newest arena. Each move, though small in scale, chips away at America’s assumption of naval supremacy in the Indo-Pacific.
The patrol may also have been a pointed signal to AUKUS, the U.S.-U.K.-Australia pact to supply Canberra with nuclear-powered subs. Chinese strategists have watched AUKUS developments with alarm, and closer cooperation with Russia offers Beijing a way to answer undersea with undersea.
The real test will come if — or when — Russian and Chinese nuclear subs begin operating together. That would suggest not just joint drills, but deeper technology-sharing on the most sensitive warfighting platforms. For now, the submarine patrol shows a quasi-alliance still feeling its way, bound by mutual convenience and mutual suspicion in equal measure.
For the United States, the danger may lie not in the patrol itself but in overreaction. The more Washington doubles down on force projection, the more Moscow and Beijing are pushed into each other’s arms. That cycle — action and counter-reaction — is what gives modest gestures like this their outsized strategic weight.
