Chepkorir established herself among the top half marathon runners in the world with a win at the Berlin Half Marathon in March 2010, running a personal best of 69:43 minutes to beat Eunice Kales. She returned to the German city for the BIG 25 Berlin race, and placed third. She was selected to compete for Kenya at the 2010 IAAF World Half Marathon Championships but injury curtailed her season before she could make her international senior debut there.