Chinese and Russian warships form a mixed formation and set out for mission areas in waters near Vladivostok, Russia during the Joint Sea-2025 naval drills held from August 1 to 5, 2025. Photo: Screenshot from the official WeChat account of the Chinese People's Liberation Army (PLA) Navy

China and Russia have wrapped up their five-day Joint Sea-2025 naval drills near Vladivostok, Russia on Tuesday and are proceeding to conduct a maritime joint patrol in the Western Pacific on Wednesday. Chinese military affairs experts said involvement of submarine and the theme of "jointly countering security threats in the Western Pacific" are hot topics of the event. 

Warship formations from the two countries have completed multi-course exercises featuring joint air defense, joint naval warfare, joint anti-submarine and anchorage defense from Sunday to Tuesday, and they will proceed to conduct a maritime joint patrol, China Central Television (CCTV) reported on Tuesday.

Held from Friday to Tuesday, China-Russia joint naval exercises were split into two parts. During the first two days, the events were mainly held at the harbor, where the two sides held tactical researches, professional exchanges, military visits and deck receptions. The sea phase started on Sunday, in which Chinese and Russian warship formations carried out multi-course training exercises featuring submarine rescue, joint anti-submarine, air defense and naval warfare, including the actual use of weapons, according to a previous statement from the Chinese People's Liberation Army (PLA) Navy.

Involvement of submarine as well as the international debut of the PLA Navy's comprehensive rescue ship Xihu in submarine rescue training sessions have been some of the highlights of the drills, observers said.

During a submarine rescue training session on Sunday, a Russian submarine grounded on the sea bed at undisclosed waters outside of Vladivostok sent a rescue request to the Xihu, the PLA Daily reported on Tuesday.

The Xihu located the Russian submarine through its sonar and underwater television systems, before releasing a deep-submergence rescue vehicle. The rescue vehicle dived deep to reach and dock with the Russian submarine in mock distress, before again reaching the surface, completing its mission, according to the report.

The Xihu is the PLA Navy's latest type of comprehensive rescue ship that was commissioned in early 2025, a commanding officer told the PLA Daily, noting that the result of the training exceeded expectations, as the rescue mission was completed faster than expected.

Chinese military affairs expert Wang Yunfei told the Global Times that the comprehensive rescue ship Xihu can host maritime rescue missions on the water surface and submarine rescue missions underwater.

Since many submarine data, such as noise characteristics, are supposed to be classified, the involvement of actual submarines in the exercises highlighted the deepening of China-Russia military ties, Wang said.

The PLA Navy said that the theme of the exercises is "jointly safeguarding strategic maritime routes" and "jointly countering security threats in the Western Pacific." After wrapping up the drills, the Chinese and Russian sides will hold a joint maritime patrol in related waters in the Western Pacific.

Zhang Junshe, another Chinese military affairs expert, told the Global Times that this is the first time "jointly countering security threats in the Western Pacific" was listed as a theme of the Joint Sea series exercises in addition to "jointly safeguarding strategic maritime routes." The routine joint maritime patrol in the region not only showcases the two navies' capabilities, but also demonstrates their firm determination in safeguarding regional peace and stability, deterring potential security threats, and creating a favorable environment for peaceful development in the region.

Reiterating that the China-Russia joint drills are not targeted against a third party, Zhang said that the event aimed at boosting the two countries' defensive combat capabilities and safeguarding sovereignty, security and development interests. By contrast, countries like the US and Japan have been frequently holding joint military exercises in recent years targeting others, with a strong cold war mentality of putting pressure on other countries, moves that sabotage peace and stability in the Asia-Pacific region, Zhang said.

Both China and Russia are permanent members of the UN Security Council as well as anti-fascist forces in the World War II. This year marks the 80th anniversary of the World Anti-Fascist War, and the two countries are moving together to oppose the revival of militarism and defend the post-war international order, Zhang said.