Walters was born and raised in the Mumbles, near Swansea. Her father died when she was very young, leaving her mother to raise four children under four years old. In 1973, aged 11, she took over her brother's paper round, covering Mumbles Head every day, an experience she described at length on BBC Radio 4 in January 2012. When she was 14 she qualified as a lifeguard, working on the local beaches.
In December 2011 she appeared in the pantomime Cinderella at the Riverfront Arts Centre in Newport.
Walters has worked frequently in television, but is best known for playing Gwen West in the BBC comedy-drama Gavin & Stacey. She was one of eight celebrities chosen to participate in an intense week learning Welsh in an eco-friendly chic campsite in Pembrokeshire in the series cariad@iaith:love4language shown on S4C in July 2011. Walters made a guest appearance in Casualty as Carrie on 3 February 2018.
