On 25 September 2021, she became the first woman to referee a Premiership Rugby Union Match when she took centre field for a fixture between Harlequins and Worcester Warriors at the Stoop.

Aged 17, she decided to retire from playing the sport after an injury, and took up refereeing instead,[1][5] initially part time, whilst also working for a waste management company.

[13] In August 2020, Cox became the first woman to officiate a Premiership Rugby league match, when she was one of Wayne Barnes' assistants for a fixture between Bath and Wasps.

[18] On 25 September 2021, Sara Cox became the first woman to referee a Premiership Rugby League Match when she took centre field for a fixture between Harlequins and Worcester Warriors at the Stoop.

[20] Cox was appointed Member of the Order of the British Empire (MBE) in the 2023 Birthday Honours for services to rugby union football.