Edie Smart, from the Monkseaton area, was rescued from the water near the south end of Whitley Bay beach in North Tyneside shortly before 5pm on Thursday, Northumbria Police said.
She was taken to hospital, where she died on Monday.
“This is an extremely tragic incident, and our deepest condolences go to Edie’s family and friends,” Northumbria Police said.
“Our specially trained officers will continue to provide them with the support they need at this time.
“We ask that their privacy be respected as they begin to come to terms with the loss of their loved one.”
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RNLI lifeguards and the Tynemouth RNLI lifeboat crew responded to the emergency at Whitley Bay Beach.
The RNLI said in a statement: “We would like to offer our heartfelt thoughts and condolences to the family and friends of the young girl who tragically lost her life during an incident on Whitley Bay beach.’
“This is a deeply upsetting incident, and our focus remains on supporting the agencies involved. We would respectfully ask that people avoid speculation while the circumstances are fully understood,” it added.
