The South China Sea is a marginal sea south of China . It is a part of the Pacific Ocean , occupying an area from Singapore to the Strait of Taiwan of around 3,500,000 kmÂ . The South China Sea is a marginal sea that is part of the Pacific Ocean , encompassing an area from the Singapore and Malacca Straits to the Strait of Taiwan of around 3,500,000 kmÂ .