Dr. Barbara Morrongiello, a psychology professor at the University of Guelph who holds a Canada Research Chair in child and youth injury prevention, conducted a study with her colleagues looking at the safety of children while they swim. She concluded that parents often overestimate their childs ability to swim compared to the assessment of instructors. Swimming lessons can make a child more confortable in the water and "parents may think they won't have to supervise as closely" Morrongiello tells Global News [1]. Swimming lessons also don't prepare children for accidents where they may panic and feel heavier with shoes and clothes on. 

"Another thing that parents don't always realize is that drowning happens quickly and silently. It's not often the case that children are able to call for help or splash around. Once their lungs fill with water, they're going down and they're going down quickly," Morrongiello tells CTV News [2]. 

Always keep toddlers within arm's reasch when they are around water and keep a constant eye on them.