A 21-year-old man was using an ATM machine on Harbour Tce about 6.30pm when the youths passed in a car, pointing the air pistols in his direction.
He called police, and followed the vehicle to Elder St, off Pitt St.
Senior Sergeant Craig Brown said last night the man "effectively blocked their way out," until police arrived.
The youths had been charged with unlawfully presenting an air pistol.