Born in Thessaloniki in 1927, the son of Asia Minor refugees, Kostas was arrested during the Axis occupation of Greece and sent on foot to Nazi forced labour camps in Germany.
However, he managed to escape near Vienna and stole a military uniform which he used to disguise himself as a German until the end of the war.
After the end of the war, Sarantidis went to Rome, and tried to be repatriated to Greece. This, however, proved impossible as he lacked any identity documents. Without any means of supporting himself, Sarantidis was lured into the French Foreign Legion. After joining the legion, Kostas was initially moved to Algeria and landed to Indochina in 1946. While there, he and the other legionnaires were told that the duration of their deployment would be short and that their mission would be to disarm the Japanese and restore order.
After two months with the Legion, he contacted Viet Minh spies and defected to them, carrying with him his rifle and a machine gun. He was given the name Nguyễn Văn Lập and served in various posts, participating in many battles. Eventually he rose to the rank of captain. In 1949, he was admitted to the Communist Party of Vietnam.
|Sarantidis with the legendary General Võ Nguyên Giáp.|
After his repatriation to Greece in the 1960s, Kostas joined the Communist Party of Greece (KKE) and worked for helping Vietnam as well as promoting Greek-Vietnamese relations.
He has received many honors by the state of Vietnam. In 2013, he was named a Hero of the People's Armed Forces. Additionally, he has been awarded several honorary titles by both the Vietnamese Party and State, including the Friendship Order in 2011, the Victory Medal, Third Class and the Resistance War Medal, Second Class