Russia and China have conducted their first-ever joint submarine patrol in the Pacific. The patrol by diesel-electric attack submarines began in early August, and the Russian sub involved, the Volkhov, covered around 2,000 miles during its voyage from its Vladivostok base. The subs patrolled in the Sea of Japan and the East China Sea. China and Russia have been stepping up military cooperation in the past several years. In 2021, in a voyage billed as the first joint China-Russia naval patrol in the western Pacific, a flotilla of ten Chinese and Russian warships made a circumnavigation of Japan's main island. Joint air and sea patrols have occurred off Alaska since 2023, including a joint patrol of four China Coast Guard vessels and two Russian Border Guard vessels patrolling in the Bering Sea near the US-Russia maritime border last year. The USCG was monitoring the activities of five Chinese research ships in US Arctic waters this month.