日本陸上競技選手権大会
Arai returned to competition in 2012 and won her first national title at the 2012 Japan Championships in Athletics, as compatriot Hayakari (nearing forty) faltered in the final. Arai's winning time of 9:55.93 minutes was not sufficient for selection for Japan at the 2012 Summer Olympics, however. The following year she retained her steeplechase title at the 2013 Japan Championships in Athletics and placed fourth at the 2013 Asian Athletics Championships.