He played for the Chelsea Academy for five years, winning numerous honours including the Premier League Under-15 International Tournament where he scored in the final during a 2–1 victory over Manchester City.
[5] In March 2017, he was signed by Crystal Palace to play in their Under-18 team, where he helped the side win the southern league in his first season.
[7] After making only three substitute appearances for Balzan, Donkin was loaned to fellow Maltese Premier League side Mosta until the end of the season.
In October 2017 it emerged that Taiwan head coach Gary White was seeking European based players with Taiwanese heritage to represent the team, having also called up Ross County midfielder Tim Chow.
He returned to the national team in December for the 2017 CTFA International Tournament, earning plaudits as he appeared from the bench in all 3 games, overall assisting 2 goals and hitting the crossbar in his performances.