Coughlan's success with Ennis saw him progress to regional squads with Munster and join the National Talent Squad. During the 2020–21 season, he trained with Munster's senior squad on several occasions, providing cover at scrum-half during periods of injury and international absence, and travelling with the matchday squad for league and European fixtures, whilst also representing the province at 'A' level. Ahead of the 2021–22 season, Coughlan joined Munster's academy as one of three year one recruits. Following the disruption caused by the province's recent tour to South Africa, Coughlan made his senior competitive debut for Munster in their opening 2021–22 Champions Cup fixture away to English club Wasps on 12 December 2021, coming on as a replacement for Conor Murray in the province's 35–14 win, alongside fellow Ennis RFC men Conor Moloney and Tony Butler.
