The Humber coastguard said it received multiple 999 calls reporting that a man had come off the craft near South Shields Pier on Saturday afternoon.
The Tynemouth RNLI inshore lifeboat arrived at the scene and recovered him from the water but he was pronounced dead.
A crew on a training exercise responded to the call.
Adrian Don, from Tynemouth RNLI, said they were able to respond instantly when the call came from the coastguard.
"We sped across, and came upon one casualty within the water", he said.
"He was brought onto the lifeboat but wasn't breathing, so we tried to resuscitate him while we sped back here, but unfortunately he died."
Northumbria Police said an investigation was under way.
A man has died after getting into difficulties on a water bike in the sea off the South Tyneside coast.