It refers to the section of the South China Sea which falls within the 200 Nautical Miles Exclusive Economic Zone and Territorial Waters of the Philippines, as prescribed by UNCLOS.

ADMINISTRATIVE ORDER NO. 29, ISSUED IN 2012 - Officially renamed the waters west of the Philippines as the West Philippine Sea. This includes parts of the South China Sea that are within the Philippines' Exclusive Economic Zone (EEZ), meaning areas where the country has special rights to use and protect resources. The order highlights the Philippines' ownership and control over these waters and requires the name "West Philippine Sea" to be used in official maps and documents.