The pedestrians were injured in the collision on the 25500 block of PCH between Corral Canyon and Puerco Canyon roads.
An adult and a child were reportedly struck in front of the Malibu RV Park. The two were hospitalized in critical condition at UCLA Medical Center.
Deputies were searching the area for the hit-and-run vehicle and driver, according to the sheriff's department.
The Malibu sheriff's station said PCH was reopened in both directions at about 9:45 p.m.
City News Service contributed to this report.