Ethel Bieber was born in Winnipeg and began her swimming career at the age of ten years when she joined the Women's Amateur Swim Club at the Sherbrook Pool. As a teenager from 1932 to 1938, Bieber's numerous club championships at the juvenile, junior, and senior levels prepared her for further success in provincial and national competition.
At fourteen years of age, Bieber won her first national title at the Canadian junior swimming competition in 1934, and this triumph was complemented by her Manitoba half-mile victory in 1935. Bieber enjoyed a phenomenal year in 1936 when she established provincial records as the junior champion in the 200, 100, and 50 yard freestyle events. In 1937, she was the provincial champion and record holder in 40 and 100 yard freestyle competition and was a member of Manitoba's team at the British Empire Games Trials. Unfortunately, the outbreak of the Second World War in 1939 prevented Bieber from competition at the international level. Her final individual national title was won in the 200 yard freestyle category in 1941.
Following the British Empire Games Trials, Bieber continued to compete in numerous swimming events. From 1938 to 1940, she won three consecutive Winnipeg Free Press Pier to Pier Championships held at Winnipeg Beach. She was a member of the Canadian champion and record holding 400 yard freestyle relay team in 1939 and, with a team that included Margaret Taggart, Patricia Jackson, and Catherine Gordon, she attained the national 200 yard freestyle relay title in 1940 and set Canadian records in the same event from 1940-42. This team won its final national championship with a record victory in the 400 yard freestyle event in 1943.
As an accomplished distance swimmer, Bieber was the Manitoba One Mile champion from 1937-41 and the Western Canadian One Mile champion from 1937-40.