Education
Mullen attended Ysgol Eirias in Colwyn Bay, North Wales and was a member of Rhos on Sea Cycling Club, the same club as Team Sky general manager and former head of the British cycling team Dave Brailsford. In February 2014, Ryan finished 4th in the Elite Men"s Individual Pursuit at the UCI track world championships in Cali, Colombia.
Career
He will join the UCI World Tour team Cannondale for the 2016 season. He rode at the 2015 UCI Track Cycling World Championships, where he came seventh in the individual pursuit. In August 2015, it was announced that he had signed to ride in the UCI WorldTour for Cannondale–Garmin from 2016.
Mullen rode with Cannondale-Garmin as a stagiaire in the 2015 Tour of Britain, then competed in under-23 time trial at the 2015 world championships.