Walters was elected to the Senate at the December 1975 federal election, which followed the dismissal of the Whitlam Government. She was placed fifth on the Liberal Party ticket, defeating two sitting senators (Eric Bessell and John Marriott) for preselection. She became the first woman to represent Tasmania in the Senate, and only the second Tasmanian woman elected to parliament as a whole (after Enid Lyons, MHR 1943–1951). Walters was re-elected to the Senate in 1977, 1983, and 1987, in each occasion placed either first or second on the ticket. She announced her retirement in September 1991, with her final term ending in June 1993.