At the start of 2011 he improved his half marathon best to 1:00:23 hours in winning the Azkoitia-Azpeitia Half Marathon.[7] At the Chuncheon Marathon he outran his teammate Jonathan Kosgei Kipkorir and won the race in a personal best of 2:07:03 hours – a course record and personal best by more than two minutes.[8] He ended the year with a third place at the Zhuhai Half Marathon, losing out in a sprint finish.[9]
Biwott began 2012 with his first sub-one hour half marathon; his finishing time of 59:44 minutes was enough to win the Paris Half Marathon in a course record.[10] Reaching a new career high, he recorded a marathon best of 2:05:11 hours to win the Paris Marathon a month later. He took the lead after the halfway point and continued at a fast pace to claim the prestigious course record.[11] In the latter half of the road racing season he won both the Beach to Beacon 10K and the Falmouth Road Race.[12] He was a comfortable winner at the Philadelphia Half Marathon, finishing forty seconds ahead of the field.[13]
At the 2016 London Marathon he improved his career best to 2:03:51, coming second behind Eliud Kipchoge and placing him sixth on the all-time ranking list.