Fatuma Kadir was found more than 200 miles away from her home on Saturday afternoon following an appeal by her parents, Sky News reports.
The schoolgirl was reported missing just before 10.45pm on Thursday in what police described as “every parent’s worst nightmare.”
Speaking at a news conference, her father Asheem had described his daughter’s behaviour as “normal” before she left and said he had “no idea what’s caused this.”
“Why she went to London we have no idea,” he added.
Fatuma was discovered safe and well after a police revealed she had undertaken a four-hour train journey to central London.
DCI Paul Rollinson, of Greater Manchester Police, said: “She was found in London earlier today so we are now working to reunite her with her parents, who are as you can imagine, incredibly relieved.
“The last couple of days have been every parent’s worst nightmare, so I know they will agree with me when I say a huge thank you to everyone who has shared our appeal to find Fatuma. Your help has been invaluable, so thank you.”
Fatuma apparently wanted to move to London when she was older and took it “quite seriously”, according to friends and relatives.
Greater Manchester Police said the child was seen boarding a train from Manchester Piccadilly just before 9.30pm to Birmingham New Street,
From there, she caught another train to London Euston and arrived at 1.13am the following day.
CCTV footage revealed that the schoolgirl was travelling with a man and a woman.
Detectives had released an image of the three people in an appeal for information.