Subhaan Ali, believed to be of Pakistani origin, was playing tombstoning with his friends in the Fitzwilliam Canal of the town last night when he disappeared.
His body was eventually recovered later that night after a huge rescue operation was launched by specialist emergency services teams, including crews from South Yorkshire Fire and Rescue.
Tombstoning is a game which involves jumping from height into water.
"This 11-year-old boy was actually taking part in a pastime that boys of his age call tombstoning. Unfortunately it is aptly named. It's a very dangerous pastime," firefighter Gary Willoughby local Sheffield Star newspaper.
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"Following an extensive search of a Rotherham Canal yesterday, we can confirm that specialist teams have recovered the body of an 11-year-old boy," South Yorkshire Police said in a statement on Facebook.
"Police received a report at around 7pm that a boy had been seen entering the canal, off Stone Row Way, but had disappeared soon after," they said.
"Specialist resources attended the scene, including South Yorkshire Fire and Rescue and the Ambulance Service. The body of the 11-year-old was found in the water at around 11pm.His family has been informed and are being supported by officers. The circumstances are under investigation," they added.