Mosop won the men's race at the 2010 Stramilano Half Marathon, clocking 59:20 for the win over Silas Kipruto. His coach stated that Mosop was progressing as a road runner and might make a move to the marathon distance. Attempting to defend his title at the Giro Media Blenio 10K (which he won in 2009), he finished second in a sprint finish just behind Imane Merga. He was chosen for the Kenyan team at the 2010 IAAF World Half Marathon Championships and he finished in tenth place. At the Zevenheuvelenloop 15K race, he was off the pace and finished sixth – almost two minutes behind Leonard Patrick Komon who set a world record.