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. In November, it was announced that Donkin had also been called up after impressing for the national under-19 team during training. He made his debut at the age of 16 as an 85th-minute substitute but could not prevent Taiwan from being eliminated from Asian Cup qualification at the hands of Turkmenistan. 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.