The girls, aged 15 and 17 at the time, were hit while crossing Lafayette Boulevard in Old Longueuil on Jan. 16. The driver took off without offering help to the injured pedestrians.
Police set up a command post in the area, looking for information on the driver.
On June 4, police executed an arrest warrant for the 18-year-old. He was taken into custody near his Saint-Hubert home. His car, an Audi A6, was also seized.
He is expected to appear in Longueuil court tomorrow and faces a charge of failing to stop at the scene of an accident involving bodily harm.