Strategists in Canberra should factor in the plausible risk of Russian participation in a Western Pacific conflict, especially action by Russian submarines.
Russia has modernised its Pacific submarines and has a clear reason for using them: increasingly dependent on China economically and strategically, it could not afford to see China fail in an attempt at subjugating Taiwan. If China invades Taiwan, Russia may well act, particularly by complicating Japan’s attempts to come to Taiwan’s aid.
As Australia’s relationship with Japan goes from strength to strength, Western sanctions have isolated Russia from once critical European trade, forcing it to rely on trade with Indo-Pacific states, particularly China.
China is not only Russia’s largest export market but is also the main external state sponsor of Russia’s war in Ukraine, providing economic, diplomatic and technological support. A Western blockade of China in a conflict would both weaken Russia’s main patron and functionally cut Russia off from trade with the entire Eurasian continent when coupled with existing sanctions.
If a Chinese invasion of Taiwan were to fail, Russia would be in a highly vulnerable international position, with its attempts to upend the liberal international order thwarted and its European ambitions untenable. Therefore, one cannot assume that Russian support for a Chinese invasion of Taiwan would be merely tacit, as Chinese support has been for Russia in Ukraine.
Seemingly recognising its position, Russia has undertaken a campaign of rapid naval modernisation in the Pacific, particularly regarding its fleet of advanced nuclear submarines. Indeed, its Pacific nuclear submarine force rivals China’s in size and sophistication.
Russia has been systematically replacing its ageing Soviet-era submarines, with 13 new submarines provided to the Pacific Fleet between 2013 and March 2025, eight of them nuclear-powered.
Russia’s submarines are concentrated in a region of the North Pacific that’s relatively small, potentially freeing China to focus its forces elsewhere.
This has continued largely unhindered by the war in Ukraine. Russia has around 25 submarines in the Pacific. Twelve are nuclear-powered, though five of those are ballistic missile submarines, which carry part of Russia’s strategic nuclear deterrent and probably wouldn’t have a combat role in a Western Pacific war.
Russia’s nuclear-powered submarines are among the most advanced in the world, leading China to seek Russian help in developing its own nuclear-powered submarines, of which it currently operates around 14 – again, including ballistic missile boats. Although China’s rate of nuclear-powered submarine production far outpaces Russia’s, for the next few years Russian military support in the Pacific would be about half their combined nuclear-powered submarine presence.
Also, Russia’s submarines are concentrated in a region of the North Pacific that’s relatively small compared with China’s larger area of responsibility, maximising Russian potency in the Northwest Pacific theatre and potentially freeing China to focus its forces elsewhere.
It is not surprising then that Russia’s joint exercises with the People's Liberation Army Navy have increased dramatically in frequency, scale and aggression, particularly in the Sea of Japan.
Importantly, Japan and Russia are in an ongoing territorial dispute over the Kuril Islands. In September 2024, the Japan Air Self-Defence Force scrambled several fighter jets and fired flares at a Russian plane that had violated Japan’s northern airspace while China and Russia conducted joint naval exercises in the Sea of Japan. In August 2025, Russia and China conducted their first joint submarine patrol, again in the Sea of Japan.
Russia has developed the impetus and the means to assist China militarily in the Pacific by complicating the strategic planning of key Australian and US partners.
Actions such as these have made some in Tokyo nervous and could have significant strategic consequences, given that Japan is home to the United States’ Seventh Fleet – the US’s largest forward-deployed fleet, which would be crucial in responding to a Chinese attack on Taiwan.
With its Pacific fleet, Russia seeks to complicate the strategic calculus of US allies in North Asia, such as Japan and South Korea, in a Taiwan invasion scenario by threatening to hinder efforts to come to Taiwan’s aid. Russia’s highly concentrated fleet of quiet nuclear-powered submarines could cut Japanese and South Korean undersea cables in ways that would prove more difficult for China’s currently noisier submarines.
Russia’s advanced missile strike capabilities constitute a further threat. Missiles launched from the Russian-controlled parts of the Sea of Japan or the Sea of Okhotsk off Japan’s northern coast would give the Japanese much less time to respond than those coming from closer to China. A German defence strategy document issued on April 22 envisions a scenario in which the Russian Pacific Fleet is used to tie up US forces, thereby complicating US deployments to Europe to resist a simultaneous Russian invasion of the Baltic states.
Russia’s participation in a Pacific conflict is not guaranteed, and its European interests may well take precedence. However, Russia has developed the impetus and the means to assist China militarily in the Pacific by complicating the strategic planning of key Australian and US partners.
As Australia’s relationship with Japan deepens, Japan has arguably become Australia’s closest regional defence partner. So Russian submarines need to become a factor in Australian defence planning.
Article reprinted with permission from the Australian Strategic Policy Institute's analysis and commentary site The Strategist.