Marc-André Gagnon, Urgences Santé’s chief of operations, said one managed to swim to shore.
The other had to be rescued from the river by the Montreal firefighters' nautical team. Gagnon said both were wearing lifejackets.
He said that waters are usually high at this time of year, making currents stronger.
Gagnon said the boaters are in stable condition, but have been taken to hospital for hypothermia treatment.