It happened just before 1 p.m., according to Quebec provincial police.
The helicopter the man was piloting crashed into Lac Britannique for unknown reasons. He was the only occupant.
Lac Britannique is about 70 kilometres northeast of downtown Ottawa, near the small town of Saint-Sixte, Que.
The man managed to get out of the helicopter and swim to shore after the crash, police said.
Police and officials from the Transportation Safety Board are investigating.