S-Fone is a mobile communication operator in Vietnam that uses the CDMA technology. Founded on July 1, 2003 in Ho Chi Minh City, Vietnam, S-fone became the third network of Vietnam, breaking the duopoly of the two VNPT operators. It is the trademark of S-Telecom (CDMA Mobile Phone Center) (set up as a joint venture between Saigon Postel Corp. (SPT) and Korea SK Telecom). SK Telecom decided to leave the partnership in 2010.