Zilpha Grant had the following podium finishes at major championships: 3rd in the 1938 British Empire Games 4×110 yards Freestyle Relay (with Edna Hughes, Margery Hinton, and the non-Olympian Joyce Harrowby); 3rd in the 1938 European Championships 4×100 metres Freestyle Relay (with Margery Hinton, Olive Wadham, and the non-Olympian Joyce Harrowby). Grant also competed in the 1938 British Empire Games 110 yards Freestyle and in the 1938 British Empire Games 110 yards Backstroke. In the British Empire Games she competed for England.