Career
Clarkin has played most of his professional rugby career at the top level in France and is captain of the Top 14 team Union Bordeaux Bègles. He has been described as being a player that is able to orchestrate play, as well as having a strong work ethic and hitting the ball up into the opposition allowing space for the back line. Clarkin arrived in France in July 2003, aged 22, to play for Bordeaux-based CABBG in the PROD2 league.
In 2004 he moved to United States Montauban where he played from 2004–2010, captaining the side in the 2009-2010 Top 14 season.
Montauban were liquidated at the end of the 2009-2010 season due to financial problems and Clarkin signed a 2-year deal with the Pro D2 team Union Bordeaux Begles (UBB) in April 2010. He is the current captain of UBB.