Cotterill is a product of the Swansea City academy which he joined aged 7 and he signed his first professional contract in June 2022.
[1] On 9 August 2022, Cotterill made his senior debut for Swansea City as a second-half substitute in 2–2 loss on penalties to Oxford United in the EFL Cup.
[2] In August 2023 Cotterill joined EFL League Two club Stockport County for the duration of the 2023–24 season.
[3] Cotterill made a number of substitute appearances for Stockport, notably featuring in an 8–0 win over Sutton United F.C where he scored his first senior goal,[4] before being recalled in January 2024.
On 30 July 2024, Cotterill returned to League Two, joining Swindon Town on a season-long loan deal.