Reached 200m semi-finals at the 2011 IAAF World Youth Championships clocking 21.62. Reached the second round of the 100m at the 2012 IAAF World Junior Championships in 10.70. 23rd in 4x400m relay at 2013 World Chamionships.
Mokamba, son to former international Elkana Nyangau, who is also his coach, is one of the most promising sprinters in the country. Mokamba clocked personal best 20.50 to hit the World Championships qualifying time to win the national title on July 11before improving his time to 20.48 with victory during the World Championships trials on August 1. He was part of the 4x200m team for the 2015 World Relays but were disqualified in the first round. He set a new national 100m record of 10.23 during the nationals on July. His 4x400m team finished 23rd at the 2013 World Championships.
Represented Kenya in th IAAF World Athletics Championships 2015 in Beijing China