Lyn Bell joined with Dawn Fraser, Jan Murphy and Robyn Thorn to claim the silver medal behind the United States in the women’s 4 x 100 metres freestyle relay at Tokyo 1964. Jan Turner swam in the heat but was replaced by Fraser for the final. Bell finished eighth in the 100 metres freestyle, behind Fraser’s third gold medal in succession in the event. She competed at Mexico City 1968, finishing seventh in the 200 metres freestyle, fourth in the 4 x 100 metres freestyle relay as well as swimming in the preliminaries of the 100 metres freestyle and the medley relay.
At the 1962 Perth British Empire and Commonwealth Games, Bell won a gold medal in the 4 x 110 yards freestyle relay. At the 1966 Kingston British Commonwealth Games, she won a silver medal in the 110 yards freestyle and silver and bronze medals in the freestyle and medley relays respectively.