She first competed for Westbury in 2008 in the under 11s age group in the Gwent League and the BMC Cross Country Classic in Ashton Court.
[4][5][6] In March 2021, she ran a personal best time of 4:41.78 for the mile run at the 2021 NCAA Division I Indoor Track and Field Championships in Houston, Texas.
[9] Competing at the 2022 British Athletics Championship, she was a finalist in the 1500 metres after winning her qualifying heat, placing eighth overall.
[10] In January 2024, Leather won the 3000 metres race at the BMC Meeting in Sheffield, with a half-minute personal best time of 8:54.67.
[14] She won bronze over 1500 metres at the 2025 British Indoor Athletics Championships in Birmingham, on 23 February 2025, behind Georgia Bell and Revée Walcott-Nolan.