The young boy had been swimming with a group in the Snowy River in Jarrahmond, in the state’s south-east, on New Year’s Day when he got into difficulty and slipped below the surface before 6pm.
Police and the State Emergency Service searched for the boy into the night but his body wasn’t found until 10.45am.
Emergency services were contacted about that time after three swimmers got into difficulty in rough waters near the mouth of the Gellibrand River about 10.40am.
Two men in a private helicopter helped rescue the three swimmers.
They landed their aircraft and started CPR on a 35-year-old man but he could not be revived.
The two other swimmers were taken to hospital.
One was flown to The Alfred hospital this afternoon, where he is in a stable condition.
Reports will be prepared for the coroner.
Water safety has become a significant concern across the country over the holiday periods, with a spate of drownings.