A full inter-agency search of the water got underway after the alarm was raised at around 2pm this afternoon.
It's believed the boy was swimming with friends when he got separated from the group.
The operation involved the Coast Guard Rescue Helicopter 117, Coast Guard boats and divers, the County Fire Service, Gardaí and the National Ambulance Service.
The boy's body was located and taken from the water at around 4pm.
A post mortem is due to take place at Cork University Hospital.
