Preda competed for Romania in two swimming events at the 2008 Summer Olympics in Beijing. Leading up to the Games, he scored an eighteenth-place time in 1:02.16 (100 m breaststroke) to beat the FINA B-cut (1:03.72) at the European Championships five months earlier in Eindhoven, Netherlands. In the 100 m breaststroke, Preda fired off a 1:01.77 to drop his own Romanian record on a tech body suit by 0.11 of a second and tie for third with Sweden's Jonas Andersson in heat five, but failed to advance to the semifinals, finishing thirty-first overall in the prelims. Nearly a week later, Preda teamed up with Răzvan Florea, Ioan Gherghel, and Norbert Trandafir in the 4 × 100 m medley relay. Swimming the breaststroke leg in heat one, Preda recorded a split of 1:01.41, before the Romanian foursome finished the race in fifth position and thirteenth overall with a new national record of 3:38.00.