Rageb Aga made his debut for Kenya in the 2003-04 Carib Cup in the West Indies, having been called up from captaining the Under-19 side to replace Thomas Odoyo who was recovering from a knee injury. Aga acquitted himself well, taking 4 for 71 in one match, and was duly rewarded with a place in the team for the 2004 Champions Trophy. Part of the new generation of emerging Kenyan talent, Aga was tipped by Steve Tikolo,the man who skippered Kenya to the 2003 World Cup semi-final, as a possible successor down the line. The strike which followed the ICC Champions Trophy in 2004 fast-tracked that prediction, and Aga was appointed as stand-in captain for the Intercontinental Cup finals in November 2004. But studying in England made him largely unavailable and in 2007 he gained a British passport contract with Sussex where he stayed for four years without ever cementing a place and he was released in 2010.