Fatuma Kadir, from Bolton, left home on Tursday and travelled to London Euston, using several trains. She was last seen at 1.17am on Friday, police said.
CCTV images show Fatuma leaving Euston station alone but detectives say several public sightings were made around London Bridge Tube station.
The schoolgirl may have travelled to the capital to pursue her dream of owning a clothing business near Tower Bridge, Met police said.
In a statement, Asheem and Misra said: “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.”