In his first senior international appearance at the 2018 Commonwealth Games, he won two silver medals in freestyle relays.

[1] He was a member of Doncaster Dartes Swimming Club before he moved to train at Loughborough National Centre.

[2] In 2015, when he was 16, he took part in the inaugural European Games in Baku, Azerbaijan, and won a silver in the 200m individual medley.

[3] In 2017, at the British Championships in Sheffield, he broke the English record for his age group in 200m individual medley, winning the event at under 2 minutes.

[4] Parkinson made his first senior appearance in an international competition at the 2018 Commonwealth Games held at the Gold Coast, Australia.