Investigators say the two were walking near a school in the 1200 block of Citadel Drive when they were hit at 3:08 p.m. PT.
Coquitlam RCMP Cpl. Jamie Chung said police are still in the early stages of the investigation and don't have much more information.
"Both pedestrians, being a man and a boy, have been transported to a hospital with serious injuries," he said.
"Coquitlam RCMP traffic services are investigating, along with the help of ICARS [Integrated Collision Analysis and Reconstruction Service] and general duty officers."
The driver stayed at the scene. Chung said the area is closed to traffic while police conduct their investigation.