Emergency services were called to the River Lee Canal near Riverside Close just before 6.30am on February 23.
The man was rescued from the water and treated by paramedics before being taken to hospital.
He was pronounced dead shortly after.
His next of kin have been informed and are being supported by officers.
The death is being treated as unexpected and the circumstances remain under investigation.
A spokesperson Metropolitan Police said: “Police were called to reports of a man in the River Lee Canal close to Riverside Close, Upper Clapton, at 06:29hrs on Sunday, 23 February.
“Officers attended alongside the London Ambulance Service and the London Fire Brigade. A man in his 20s was pulled from the water and treated by paramedics before being taken to hospital.
“Sadly, he later died. His next of kin is being supported by officers.
“The death is being treated as unexpected and the circumstances remain under investigation.”
