The Southern Theater Command Navy (STCN), or the South Sea Fleet (SSF) until 2018,^[1] is a formation of China's People's Liberation Army Navy (PLAN) and the naval component of the Southern Theater Command.^[2]

In December 1949, the Fourth Field Army transferred personnel from the 15th Army to create the Guangdong Military Region Riverine Defense Command.^[3] The Riverine Defense Command commanded the Wanshan Archipelago Campaign in May to August 1950^[4] and was the "nucleus" of the South Central China Military Region Navy created by the Fourth Field Army in December 1950. The military region's navy became the PLAN's South Sea Fleet in 1955.^[5]

The SSF won the Battle of the Paracel Islands against South Vietnam in 1974.^[6][7] China's first anti-piracy patrol to Somalia deployed from the SSF in December 2008.^[8]

STCN headquarters is at Zhanjiang, with bases in Sanya and Guangzhou.^[9] The bases at Sanya include Yulin Naval Base and Longpo Naval Base, the latter for submarines.^[10] It controls coastal defenses west from to Dongshan County and in the South China Sea.^[9]

In 2016, subunits included:

• 2nd Destroyer Zhidui^{[note 1][12]}
• 9th Destroyer Zhidui^[12]
• 11th Fastboat Dadui^{[note 2][12]}
• Unidentified Fastboat Zhidui^[12]
• Operations Support Ship Zhidui^[12]
• 8th Air Division^[12]
• 9th Air Division^[12]
• 1st Marine Brigade^[12]
• 164th Marine Brigade^[12]