William Mannion

William Mannion started out in the AFC Wimbledon youth system before Hull City signed him in July 2016, in a deal that included a £100,000 compensation fee and add-ons tied to first-team and international appearances. Those add-ons went largely unclaimed: he made no league appearances for Hull, restricted to a single EFL Cup outing, and instead learned his trade away from East Yorkshire, out on loan at Plymouth Argyle, Aldershot Town and Kidderminster Harriers.

A free transfer took him to Cyprus in 2020, where a season with Pafos FC brought no league football, before he returned to England to sign for Cambridge United in August 2021. A loan spell at Havant & Waterlooville that autumn included an FA Cup first-round tie away at Charlton Athletic, the club he would go on to join.

Mannion signed for Charlton on a three-year contract in June 2024 and has since established himself as their goalkeeper, making 38 league appearances for the club. He was part of the Charlton squad that won the EFL League One play-offs in 2025, a result that sent the club up to the Championship.

At youth international level, Mannion earned two caps for England's Under-19s in 2016, making his debut in a 1–1 draw with the Netherlands before featuring in a 2–1 win over Hungary the following month. He had earlier trained with the England Under-16 squad.