The season began in September 2009 and ended with the Grand Final on 29 May 2010.

The ten teams competing consisted of the four Irish provinces, Munster, Leinster, Connacht and Ulster; two Scottish regions, Edinburgh Rugby and Glasgow Warriors; and four Welsh regions, Cardiff Blues, Newport Gwent Dragons, Ospreys and Scarlets.

This season saw the introduction of a play-off structure similar to the English Premiership in order to determine the overall winner.

[3][4] The Ospreys won the final, defeating Leinster 17–12 in Dublin.

Note: Flags to the left of player names indicate national team as has been defined under IRB eligibility rules, or primary nationality for players who have not yet earned international senior caps.