Fredi Rivero was set upon shortly before midnight near a bus stop on Seven Sisters Road on February 27 and died the next day.
The teenagers, 15, 16 and 17, got off a bus and surrounded the victim, a Bolivian national.
They pushed, shoved, kicked and punched him, with one of them filming the attack on her phone and grabbing his glasses.
As part of the police investigation, officers recovered CCTV footage of the assault in which the oldest girl was seen to punch the victim in the head causing him to fall backwards.
Police were called at 11.25pm to reports of the disturbance and found Mr Rivero unconscious on the pavement with a severe head injury and in cardiac arrest.
He was taken to the Royal London Hospital where he later died.
Today (June 12), the girls, who cannot be identified because of their ages, appeared at the Old Bailey before Judge Judy Khan KC.
The accused appeared from custody by video link and pleaded guilty to manslaughter.
Judge Khan ordered reports and remanded the defendants into custody to be sentenced on September 5.
Previously, police have said Mr Rivero was a “much-loved father” whose family were “devastated by his death”.
Mr Rivero’s daughter, ex-wife and cousins attended court for the hearing.
