In 2024, as a head coach, she guided South Africa to victory in a Netball World Youth Cup qualifying tournament and Kingdom Stars to a Division Two Shield title.
[6][11][16] Between 2017 and 2021, as either a player and/or coach with Gilbert Stars, Mthembu, won five consecutive titles in KwaZulu-Natal's Netball Super League.
[20] On 26 January 2007, Mthembu made her senior debut for South Africa during an away series against England.
[25] On 3 September 2017, Mthembu was a member of the first South Africa team to win a Netball Quad Series match when they defeated England 54–51.
[3][28][29] Sources:[3] In December 2021, Mthembu was head coach of a South Africa under-20 team that won a regional youth tournament.
[3][20][50] She also served as an assistant coach to both Elsje Jordaan and Jenny Van Dyk with the South Africa under-21 team.
[20][51][52][53] She subsequently guided South Africa to victory in a 2025 Netball World Youth Cup qualifying tournament.
[54][55][56] During the 2022 Telkom Netball League season, Mthembu served as head coach of Kingdom Queens.