Firefighters were called to the popular beauty spot just after 4pm and arrived to find the boy stranded on a floating raft.
Crews used a boat to reach the boy, before fitting him with a life jacket, and taking him back to land.
The boy was not injured.
A South Yorkshire Fire and Rescue Service spokesman said: "Firefighters from Aston Park, Tankersley and Rotherham were called to the country park at 4.05pm on Sunday afternoon.
"Upon arrival they found a boy stranded on a floating raft in the middle of a lake. He was not in distress or in the water, but he needed help getting back to shore.
"One of our crews took a boat with paddles to reach him, fit him with a life jacket and take him back safely.
"He wasn’t hurt in any way and they left the scene at around 5.26pm."