Carbery made his senior competitive debut for Leinster on 18 March 2016, when he came off the bench in the province's 12–6 defeat during the 2015–16 Pro12 season at the hands of Glasgow Warriors. He made his break-through for Leinster when he started at fly-half in the provinces opening 2016–17 Pro12 fixture against Benetton on 2 September 2016. Carbery scored two tries in their 20–8 victory against the Italian side.