Oisin originally interned as the assistant Strength and Conditioning (S&C) Coach with Glamorgan back in 2016. He then rejoined the club ahead of the 22/23 season, having previously worked at Northamptonshire CCC for 3 seasons as the head of athletic development. Oisin has also worked in various sports and organisations such as Munster Rugby, Leicester Tigers, the New Zealand Sports Academy, and the Chinese Olympic Committee.