Martens represented Natal at the 1990 Craven Week tournament for schoolboys and was selected for the South African Schools team in 1990. He made his provincial debut for Free State in 1991 and also played for the South African under - 23 team in 1994. In 1995 he joined Natal, playing provincial rugby and super rugby for the Coastal Sharks. At the end of the 1993 season, he toured with the Springboks to Argentina. Martens did not play in any test matches but played in three tour matches, scoring one try for the Springboks.