China and Russia are holding joint naval drills from 5-12 July in the Sea of Japan.
People's Liberation Army chief Gen Fang Fenghui said on Tuesday the aim of the drills was to deepen ties with Russia.
The People's Daily newspaper said on Friday they were part of a series of routine exercises, with the drill focusing on joint escort and the recovery of kidnapped vessels.
State media say the Chinese fleet comprises four destroyers, two guided missile frigates and a support ship.
The BBC reports the fleet left its base on Monday in China's Qingdao port for the Peter the Great Bay in Russia.
Russia is expected to deploy 11 warships, a submarine and three planes during the drills.
China and Russia conducted naval drills for the first time last year. Both countries have participated in military exercises since 2005.
The United States and Japanese navies held joint exercises last month off San Diego.