China and Russia launched the joint SEA-2025 naval exercise in the Sea of Japan off the coast of Vladivostok on August 3. According to China’s Ministry of National Defense, the three-day exercise will include a variety of integrated operations, including joint air defense, anti-submarine warfare, maritime patrols and live-fire artillery drills. The exercise will be followed by joint naval patrols in designated Pacific waters.
The exercise involves at least six Chinese warships, including Type 052D destroyers Urumqi and Shaoxing, Type 903A replenishment ship Chaganhu, a submarine rescue ship and two diesel-electric submarines. Russia has contributed Steregushchi-class corvettes, a Kilo-class submarine and auxiliary support ships from its Pacific Fleet. Several fixed-wing aircraft and helicopters are also participating, including Russia’s Ka-27 anti-submarine helicopter and China’s Z-9C shipborne helicopter.
Strengthening maritime interoperability
Despite being described by both governments as routine and defensive in nature, Joint Sea-2025 reflects the increasing level of operational integration between the Russian and Chinese navies. Since the first joint exercise in 2012, the exercises have increased in complexity, expanding from basic formation maneuvers to integrated tactical scenarios simulating multi-domain warfare.
This year’s exercises include simulated missile interceptions, integrated submarine detection and tracking missions, and joint rescue and damage control operations. Maritime interdiction exercises are also included, including integrated boarding operations and escort procedures.
Chinese and Russian defense officials emphasize that the exercises enhance maritime security cooperation and contribute to regional stability. However, analysts note that the operations also serve to strengthen each country’s regional presence in response to the US-led buildup in the Indo-Pacific.
- Russian corvette Steregushchiy operating in the Sea of Japan. The Steregushchi-class corvettes are multi-purpose ships designed to replace the aging Grisha class. They are optimized for littoral operations, anti-submarine and surface warfare, and provide naval gunfire support for amphibious landings. (Japanese MoD)
Strategic Signal and Regional Implications
Joint Sea-2025 is taking place amid increased military activity in East Asia and the Western Pacific. A few days ago, the United States announced that it had redeployed two nuclear-powered submarines to unspecified areas near Russian waters following comments by Russian Security Council Deputy Chairman Dmitry Medvedev. Although not officially linked, the closeness of these announcements has added to the symbolic nature of this year’s exercises.
For Russia, the exercises near Vladivostok strengthen its military presence in the Asia-Pacific and strengthen its defense posture in the Sea of Japan. For China, the exercises provide a valuable opportunity to test long-range operations beyond its immediate coastal waters and rehearse wartime coordination with a strategic partner.
Japan, which shares maritime borders with both countries, has expressed concern over the exercises. Tokyo’s Defense Ministry noted the increase in the pace and scale of joint Sino-Russian patrols near Japanese waters and warned of potential destabilization. South Korea and the United States are also closely monitoring the exercises.
Equipment and Capabilities on Display
The exercise showcases some of the most advanced naval assets in both fleets:
- Type 052D Destroyers (China): Equipped with HHQ-9 long-range surface-to-air missiles, YJ-18 anti-ship missiles and modern phased-array radars, these ships form the backbone of China’s surface fleet.
- Steregushchi-class Corvettes (Russia): Equipped with Kalibr cruise missiles, Radut air defense systems and Paket-E/NK anti-submarine torpedoes, these ships play multiple roles in coastal waters.
- Kilo-class submarines (Russia): Quiet and suitable for anti-submarine and anti-submarine operations in coastal environments. Their inclusion signals a focus on undersea warfare scenarios.
- Type 903A Replenishment Ship (China): Increases logistical reach, allowing Chinese surface ships to continue operations further from home.
- Naval Aviation Assets: Ka-27 helicopters (Russia) and Z-9C helicopters (China) provide airborne sonar and torpedo delivery, critical to the exercise’s anti-submarine focus.
The use of these systems suggests a deliberate attempt to replicate a high-level, multi-threat maritime environment – increasingly relevant in the context of disputed waters such as the East China Sea, South China Sea, and the Western Pacific.
- The Chinese Navy’s Type 052 destroyer Qingdao (DDG 113) was seen during a routine port visit to Pearl Harbor. The Type 052, known to NATO as the Luhu-class, was the first class of PLA Navy destroyers equipped with gas turbine propulsion and modern combat guidance systems, a significant step in China’s naval modernization. (US Navy)
Beyond the Exercises: Strategic Alignment and Global Implications
The exercises reinforce what Moscow and Beijing see as a strategic realignment. While the two powers maintain separate geopolitical goals, the US Their shared opposition to maritime dominance has created space for military coordination. The exercises signal not only strategic cooperation but also strategic communication aimed at deterrence.
For Washington and its allies, Joint Seas-2025 emphasizes the need for continued maritime presence, allied naval coordination, and investment in anti-access/area denial (A2/AD) countermeasures. Recent trilateral exercises between the U.S., Japan, and South Korea, as well as coordinated patrols involving India and Australia, suggest a region increasingly defined by multi-naval balance.
The long-term outcome of the Sino-Russian naval alliance will not be the creation of a formal military bloc, but a continued challenge to Western maritime governance assumptions in the maritime periphery of Eurasia.
- Russian Ka-27PS (NATO: Helix D) in flight. The Kamov Ka-27 is a naval helicopter originally developed for the Soviet Navy, designed primarily for transport and anti-submarine warfare. As of 2024, it is in service with several nations, including Russia, Ukraine, Vietnam, China, South Korea, and India. (US Navy)
FAQs
China and Russia say the Joint Sea-2025 exercise is routine and defensive. But experts believe the exercises also send a message to the US and its allies in the Indo-Pacific. By training together, both countries are showing that they are improving their naval teamwork and strengthening their military presence in the region.
The exercises involve some of the most advanced warships and aircraft from both sides. China has sent Type 052D destroyers, submarines and a supply ship, while Russia has included Steregushchi-class corvettes, a Kilo-class submarine and Ka-27 helicopters. These assets allow both navies to practice air defense, anti-submarine warfare, and live fire operations.
Japan has expressed concern because these exercises are taking place close to its waters. South Korea and the United States are also closely monitoring the activities. With increased patrols by the US Navy and growing cooperation between Japan, South Korea, India, and Australia, the region is seeing more military activity than ever before.
The Joint Sea-2025 exercises show how China and Russia are adjusting their strategies at sea. While they do not plan to form a formal military bloc, their joint training challenges the dominance of the US and its allies in the Pacific. This trend fits into the bigger picture of power shifts in East Asia and the broader Indo-Pacific.
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