Halton police say two people were pulled from Lake Ontario by its marine unit at Coronation Park on Monday morning.
Police spokesperson Ryan Anderson told Global News officers were called out around 10:30 a.m. following a call of “persons in distress in the water.”
A 10-year-old boy was extracted from the lake and with no injuries, according to Anderson. He was sent to hospital as a precaution.
A woman was also located in the water by Oakville Fire, removed and taken to hospital by EMS.
In an update, Halton police said the woman had died.
“Despite the lifesaving efforts of first responders and the Hospital Emergency Medical Unit, the Halton Regional Police Service are deeply saddened to report the young woman has passed away,” police said.
Authorities say the boy and the woman were not related but at the park together.
The investigation into the cause is ongoing, Anderson said.
— with files from Global News’ Isaac Callan