South Sea, South Seas or Southsea may refer to:
Bodies of water
Pacific Ocean, originally named by European explorers Mar del Sur, or South Sea
South Seas, a common name for the South Pacific
The Southern Sea, an alternate name for the Gulf of Mexico, particularly during the Mexican-American War
Southern Ocean or the Great Southern Ocean, the Antarctic Ocean and the South Polar Ocean
South China Sea, encompassing an area from Singapore to the Strait of Taiwan
Namhae (sea) or South Sea, Korean name for body of water south of the Korean Peninsula, where the Yellow Sea meets Sea of Japan
Zuiderzee or Southern Sea, a reclaimed bay of the North Sea, now IJsselmeer, Netherlands
Red Sea, also known as Southern Sea in the ancient Mediterranean world
English Channel, called the South Sea by the early Anglo-Saxons
Geographic regions and populated places
Oceania, Australia and the islands east of Australia
Nanyang (region), Chinese name for the geographical region south of China, particularly Southeast Asia
Polynesia, also called the South Sea Islands
South Seas Mandate, territories assigned to Japan by the League of Nations after World War I
Southsea, a seaside resort in Portsmouth, England, UK
Southsea, Wrexham, village in Wrexham, Wales, UK
Arts
South Seas (genre), a genre of literature and films taking place in Oceania or Pacific Islands
The South Seas (novel), a 1979 Spanish novel by Manuel Vázquez Montalbán
Other
South Sea Roller Derby, an Australian roller derby league
PS Southsea (1930), passenger vessel built for the Southern Railway in 1930
TSMV Southsea, a passenger ferry built in 1948
Mare Australe or Southern Sea, lunar mare in the southeastern hemisphere of the Moon