Southwest Cay Southwest Cay ( ; ; ) is an islet in the northern edge of Spratly Islands in South China Sea . It is part of North Danger Reef , and just 1 . 75 miles from Northeast Cay . With an area of 12 hectares , it is the sixth largest Spratly island and the second largest among the Vietnamese - occupied Spratly islands . The island is also claimed by the People ' s Republic of China , Republic of China ( Taiwan ) and the Philippines . Southwest Cay holds the archipelago ' s highest point , at 4 meters above sea level ; was once a breeding place for birds and covered with trees and guano . Export of guano had been carried out " on a considerable scale . " History . In 1933 , the French Government took official possession of the Spratley islands including North East Cay and South West Cay . Three ships , the Alerte , the Astrobale and the De Lanessan took part in the expedition . The following quotations are from an account given by H . Cucherousset in L ' Eveil economique de l ' Indochine ( No . 790 of May 28 , 1933 ) : ” Further north still , at the level of Nhatrang , is the atoll named " North Danger " , the Alerte took possession of two sandy islands ( cayes ) where it found some Japanese fishing . The De Lanessan went there too and explored the little island . The latter is perceptibly higher than the others , the highest point reaching 5 metres . The phosphate beds are considerable and were much exploited by the Japanese . " After possession had been taken , the French Ministry of Foreign Affairs published the following notice in the French Journal Officiel dated July 26 , 1933 ( page 7837 ) : " Notice concerning the occupation of certain islands by French naval units . The French government has caused the under mentioned isles and islets to be occupied by French naval units : The above - mentioned isles and islets henceforward come under French sovereignty ( this notice cancels the previous notice inserted in the Official Journal dated July 25 , 1933 , page 7784 ) . " In 1939 , Japan occupied the islands and would remain there until the end of World War II . In 1956 , France transferred the islands to South Vietnam . In 1959 , the South Vietnam ese Government renamed the Song Tử islands ( meaning twins after their resemblance to each other ) " Tây " ( meaning West ) and " Đông " ( meaning East ) respectively . They were annexed to Phước Tuy Province , South Vietnam . In 1961 , the two South Vietnam Navy cruisers , the " Van Kiep " and the " Van Don " , landed on the islands of Song Tu Tay ( South - West Cay ) . On May 24 , 1963 , the sovereignty steles were rebuilt on Song Tu Dong ( North East Cay ) and Song Tu Tay ( South West Cay ) by crew members of the three vessels " Huong Giang " , " Chi Lang " and " Ky Hoa " of South Vietnam . In 1968 , Philippines troops occupied Song Tu Dong ( North East Cay , Parola ) and Song Tu Tay ( Pugad ) . Captured by Vietnam . In 1975 , a party was held for the Philippine commanding officer at Northeast Cay . Philippine forces guarding the Southwest Cay attended the party and upon their return , found that the South Vietnam ese , who were then allies , had occupied the island in their absence . In April 1975 , there was a skirmish between the South Vietnamese Navy and North Vietnam task force on this island . The North Vietnam task force won and occupied the island . Some of the South Vietnamese who had taken over the island from the Philippines fled Southwest Cay and swam to Northeast Cay ( Philippine controlled island ) to seek refuge . Although the PRC , ROC ( Taiwan ) and Philippines all claim the island , no clashes have been recorded since 1975 .