Fatuma Kadir, from Bolton, left home without her parents’ knowledge on Thursday evening before travelling on several trains to get to London Euston at 1.13am on Friday.
Greater Manchester Police believe she was at London Bridge Tube station at 11.16am on Friday and may be in the area around Tower Bridge.
The force said it is “extremely concerned” for her welfare.
Fatuma’s parents, Asheem and Misra, said in a statement: “We miss you, we want you to come home. We want to at least know you’re safe. You’re not in any trouble. Please contact us or the police.
“If anyone knows where she is or have seen her, please get in touch with the police.
“We are in a state of shock. We want to know where she is, who she’s with, but most of all, that she’s safe. Fatuma, Please come home.”
The force is also looking to trace a man and woman who they believe were worried about Fatuma and travelled on the same train as her from Bolton to Manchester Piccadilly and then to Birmingham New Street.
Police believe the man and woman may know where Fatuma was going after arriving in London.
Fatuma, who arrived at Euston alone, is described as an Asian female, about 5ft 2, and of slim build. She was last seen wearing a black hijab with a blue headscarf and black dress.
Detectives said she had aspirations of owning a clothing company in London.
During a press conference on Friday night, Detective Chief Inspector Paul Rollinson said Fatuma may have travelled to the city to pursue her ambition of setting up a business near London Tower Bridge.
He said: “What we know is that Fatuma has got aspirations of setting up a business by London Tower Bridge. However, she might also be intending to do some sightseeing.”
Greater Manchester Police are looking for an 11 year old #missing girl from #Bolton, who was seen boarding a train to London
They're also looking to find an unknown man and woman who travelled on the same train as Fatuma Kadir, as they may know where she was going afterwards pic.twitter.com/q4pKZaInP4
— Radio News Hub (@radionewshub) July 23, 2021
Several public sightings near London Bridge Tube station have led police to believe she may still be in the Tower Bridge area.
The young girl is said to have not spoken to friends or family about her plans to catch a train to the capital.
Fatuma was described as “street smart” and “confident”, but Greater Manchester Police Detective Chief Inspector Paul Rollinson said she was still “very vulnerable”.
Police are urgently appealing for witnesses who might have seen missing 11-year-old Fatuma Kadir from Bolton.
She was last seen arriving at London Euston station at 1.13am this morning (Friday 23rd July) @itvnews pic.twitter.com/bykBdoqQnT
— Hannah Miller (@hannahITV) July 23, 2021
Mr Rollinson said: “She’s street smart, she’s got some wits about her. But she’s still very, very vulnerable at 11 years old.
“She’s never been out on her own, and she doesn’t travel to town centres on her own. She’s not been to London on her own before.
“But her family have said she’s very intelligent and can be very confident.”
Fatuma is said to have a mobile phone with her but it is currently not working.
Anyone with information is asked to call 0161 856 5757 quoting log number 3275 of 22/07/2021, or report it online at www.gmp.police.uk. Alternatively, you can contact Crimestoppers anonymously on 0800 555111.