Margaret Girvan had the following podium finishes at major championships: 1st in the 1954 British Empire and Commonwealth Games 3×110 yards Medley Relay (with Elenor Gordon and Margaret McDowell), 3rd in the 1954 British Empire and Commonwealth Games 440 yards Freestyle, 3rd in the 1950 British Empire Games 3×110 yards Medley Relay (with Elenor Gordon and the non-Olympian Elizabeth Turner). Girvan also competed in the 1950 British Empire Games 110 yards Backstroke and finished fifth. In the 1950 British Empire Games 110 yards Freestyle as well as 1950 British Empire Games 440 yards Freestyle she was eliminated in the heats. In the 1954 British Empire and Commonwealth Games 110 yards Freestyle she was eliminated in the heats and in the 1958 British Empire and Commonwealth Games 440 yards Freestyle she was again eliminated in the heats. At the British Empire Games she competed for Scotland.