While still a teenager, Claudette Masdammer competed in the 1956 Olympics for British Guiana, making her the first woman to compete for that nation, where she was eliminated in the heats of both sprint events. In 1958, she also competed in the British Empire and Commonwealth Games, again being eliminated in the preliminaries. Her best international showing was at the 1959 British West Indies Championships, the first for women. She came third in the 100 m, behind two compatriots and finished second in the long jump behind Yvonne Laidlow of Jamaica.
The following year Masdammer started her nurse's education, travelling to England in 1961. She married a fellow Guyanan, British naval officer Winston Humphrey, travelling around the world before settling in England, where she worked as a midwife in Southampton and Hythe.
Personal Bests\: 100 – 11.8 (1957); 200 – 24.0 (1957).