Toronto police Const. Wendy Drummond said the call came in at 3:50 p.m. with people reporting that a person had gone under the water.
The man was pulled from the water in life threatening condition shortly before 5 p.m.
The man was described as 24 years old, 170 pounds and not a good swimmer.
The police marine unit and lifeguards took part in the search.
Police later reported that the man died after being transported to Scarborough General Hospital.