Teams Willem van der Merwe played for

Main FCOrange Free State (1978/79-1984/85)
 Western Province B (1985/86-1986/87)
 Oxford University (1990)
Main ListAOrange Free State (1981/82-1984/85)
 Western Province (1985/86-1986/87)
Other FCSouth African Defence Force (1987/88)
 Oxford and Cambridge Universities (1990)
Other ListACombined Universities (1990)
MiscellaneousOrange Free State Schools (1978/79)
 South African Schools (1978/79)
 Orange Free State (1983/84)
 Western Province (1986/87)