Sims moved to North Queensland with his younger brother, Tariq, who had played in the Broncos' Under-20s team.
He played in 24 matches for the Cowboys in the 2011 season, and was a substitute for their qualifying final loss to Manly.
Ashton Sims led the way for NRL props in offloads in 2011, making 42 to his teammates.

Sims hit career best form for the Cowboys in 2012 averaging 108 metres and 22 tackles, he did an admirable job in the Cowboys starting pack while rep star Matthew Scott was out with a foot injury.

On 11 May 2012 it was announced that the oldest Sims brother had re-signed with the club for a further two seasons, which saw him at the club until the end of the 2014 NRL season.
Sims moved to North Queensland with his younger brother, Tariq, who had played in the Broncos' Under-20s team. He played in 24 matches for the Cowboys in the 2011 season, and was a substitute for their qualifying final loss to Manly. Ashton Sims led the way for NRL props in offloads in 2011, making 42 to his teammates.
Sims hit career best form for the Cowboys in 2012 averaging 108 metres and 22 tackles, he did an admirable job in the Cowboys starting pack while rep star Matthew Scott was out with a foot injury.
On 11 May 2012 it was announced that the oldest Sims brother had re-signed with the club for a further two seasons, which saw him at the club until the end of the 2014 NRL season.
Ashton Sims