Finnish national Cubeyda Hassan Jama, of London Road, Thornton Heath, London, was charged with "engaging in conduct in preparation for giving effect to intention to commit acts of terrorism".
He is due to appear at Westminster Magistrates' Court on Monday.
Detectives from the Met's Counter Terrorism Command arrested him at Stansted Airport on Friday.
A 19-year-old man who was arrested at Stansted Airport has been charged with terrorism offences.