The photo, which has been shared widely on Facebook, shows five small kids sitting on the bow of a speed boat.
They aren't in seats, and the children can be seen dangling their legs over the side and hanging on to a chrome railing.
At least one of them isn't wearing a life vest.
René Dumas, another boater in the area, said whoever was supervising the children wasn't using common sense.
"It's a safety issue, for sure," he said.
"If they hit a wave, it's clear the children would have fallen from the boat."
At least 20 people have drowned in Quebec this summer.
François Lépine of the Quebec branch of the Canadian Lifesaving Society said 80 per cent of boating-related drownings could have been prevented with a life vest.
He said children should always be within arm's reach when travelling on a motorboat.
Quebec provincial police say they are aware of the photo and say the children are clearly in a position that is not intended for passengers.
They say it is up to the operator to make sure everyone on the boat is safe.
The force says that type of infraction could net the boat's operator a fine of at least $440.