Coombes-Fabling played for the Waikato under-19s team at the Jock Hobbs Memorial Tournament in 2017. Playing at first five-eighth, Coombes-Fabling led Waikato to the final; they would go on to lose 30–17 in the final against Auckland.[2]
Since 2020 he has played for Waikato in the NPC. He scored 3 tries in the 2020 season.[3] On 24 September 2021, Coombes-Fabling scored two tries in a winning effort against Tasman which moved Waikato to the top of the NPC Premiership Division standings.[4] On 1 October he scored a hat-trick in a 38–28 loss against Northland.[5]