Career
He normally plays as a Wing, but has occasionally played Fullback. O'Mahony plays club rugby for Garryowen Football Club. He was promoted to a development contract with the senior squad for the 2013–14 season.
O'Mahony made his debut for the senior team on 19 April 2013, starting against Newport Gwent Dragons in a Pro 12 fixture and scoring a try. O'Mahony signed a one-year development contract extension in March 2014. He signed a two-year contract extension in February 2015.
O'Mahony made his debut for Under-20 on 14 February 2009, coming off the bench against Italy Under-20 and scoring a try in the 2009 Under-20 Six Nations Championship.
