Guinness A League

The Aviva A League was launched in 2003. It runs parallel to the Aviva Premiership. Split into Northern and Southern conferences, it comprises 12 sides. Premiership rugby union clubs select players from their Academy and First Team squads to make up their A League teams. This gives both young and experienced players the opportunity to play competitive rugby week in week out. Players from feeder clubs are allowed to play under dual registration for additional development benefit.

After the conferences are complete the top Northern side meets the top Southern side to decide the championship.

Northern conference:

Southern conference:

...
Wikipedia