A 16-year-old from Tilbury drowned on Wednesday despite rescue efforts.
Essex County Ontario Provincial Police (OPP) said they received a report at 2:24 p.m. of an "individual in distress" in Lake St. Clair at Lighthouse Cove.
Emergency responders arrived at the scene in Lakeshore, where officers said they found an unresponsive person in the water.
The individual was taken to a local hospital where they were pronounced dead.
The OPP won't release the victim's name at the request of their family.
"The OPP remains committed to supporting the families during this difficult time and conducting a thorough investigation," said Constable Jeanine Robertson. "As a mother myself, a police officer, I cannot stress enough the importance of always having a personal floatation device for anyone engaging in water activities, checking the weather, and understanding your swimming abilities. Lastly, it is highly encouraged to swim with a budy for added safety."
Anyone with information is asked to contact Essex OPP at 1-888-310-1122 or Crime Stoppers at 1-800-222-8477 (TIPS).
* With files from Adelle Loiselle.
