Emergency services attended the scene at Lakeside lake at around 4.10pm on Saturday.
They had received calls that a man, aged in his 20s, had got into difficulty in the water.
A body was later recovered from the lake.
“We are very sorry to report that following earlier information about an incident at Lakeside, Doncaster, a body has now been found,” a statement from the force said.
No formal identification has taken place, South Yorkshire Police added.
The man’s family have been informed and are being supported by specialist officers.