Tanner competed for Canada at the 1966 British Empire and Commonwealth Games in Kingston, Jamaica. While there, she was able to win four gold medals and three silver medals. By doing this, she became the first woman to ever win four golds at a Commonwealth Games. In 1966, Tanner was awarded the Lou Marsh Trophy for being Canada's top athlete. She became the youngest person to ever win the award. The same year, she also won the Bobbie Rosenfeld Award for Canada's female athlete of the year. 