In 1997, Cabañas represented Paraguay's U17 team at the 1997 South American Under-17 Football Championship held in Paraguay, scoring 3 goals. Two years later, Cabañas was selected in Paraguay's U20 squad to participate at the 1999 South American U-20 Championship, where he scored two goals. Paraguay qualified for the 1999 FIFA World Youth Championship as Cabañas was selected in the squad which featured Roque Santa Cruz and Nelson Cuevas.