He won the bronze medal (46.79 sec) in the 400 metres at 2005 European Athletics Junior Championships. At the age of 20, Regas finished eighth (46.23 sec) in the 400 metres final at the 2006 European Athletics Championships in Gothenburg, having set a PB of 45.60 sec at the semifinals. The same year he was third at the 2006 IAAF World Cup held at Athens Olympic Stadium with his personal best of 45.11 seconds, which still holds as a Greek national record.