Lel ran his first marathons in 2002: he failed to finish at the Prague Marathon, but in his first finish he managed to claim second in the Venice Marathon. He won Lisbon Half Marathon in 2003, 2006 and 2009, was the gold medalist at the 2003 IAAF World Half Marathon Championships, and won the Portugal Half Marathon in 2005. He made his Olympic debut for Kenya at the 2008 Beijing Olympics and came fifth in the marathon.