The Metropolitan Police have found the two girls from South Norwood that went missing on Saturday.
Zeenat Abdala, 16, and her six-year-old niece, Lutfiya Salum, both adopted from Somalia, have returned to their home country with relatives, according to the police.
The two went missing on Saturday as they left home to allegedly go to the Norwood Library on Lawrence Road in Croydon.
The pair arrived in the UK earlier this year where they were placed in foster care.
Whether the two girls will remain in Somalia is not yet known.