North Yorkshire police said in a statement that they had found Le Thi Dieu Linh, 15, "safe and well" on Monday night.
Yet the investigation into her disappearance in the county’s York City remains ongoing, they said.
They also said for operational reasons and ongoing enquiries, they could not reveal where Linh was found yet.
Linh was reported missing from her tour group in York on August 6.
Tour guide Nguyen Ba Thanh Tung of Ho Chi Minh City-based travel company Travel Plus came to the Vietnamese Embassy in London to report the case two days after it happened, the embassy said. He also reported the disappearance to local police.
After questioning Tung, North Yorkshire police let him go, and he returned to Vietnam on Saturday.
Ten people have been arrested in connection with the girl’s disappearance. Two of them remain in police custody for questioning and another, Ho Quang Ngoc, a 25-year-old Vietnamese, has been charged and appeared in court on Monday for child abduction and facilitating violation of immigration law.
Ngoc is due to appear at York crown court on September 16, police said.
Linh speaks no English, and Vietnam’s Foreign Ministry has instructed the embassy in London to keep related agencies in touch and prepare to implement necessary citizen protection measures.
The U.K. is a major destination for Vietnamese human trafficking victims, with at least 3,187 Vietnamese victims identified since 2009 until recently.
About 362 possible child victims from Vietnam were discovered in England in 2017, up more than a third over 2016.
Victims trafficked from Vietnam most commonly end up being exploited, often in cannabis farms and nail bars, but many are also sexually exploited, according to a report commissioned by Britain’s Independent Anti-Slavery Commissioner Kevin Hyland.