The move comes as Valencia undergo significant changes following the arrival of Braulio Vázquez and Javier Aguirre, with the club looking to reset after a difficult start to the season.
Despite the focus on the first-team situation, Valencia have continued working on the development of their young players.
According to Súper Deporte, the club have reached an agreement to retain Mosquera, the younger brother of Arsenal defender Christian Mosquera.
The teenager has signed a three-year contract, securing his future at Valencia as he continues his development within the club's academy.
Mosquera's agreement represents another step in Valencia's efforts to retain promising young talent during a period of significant change at the Mestalla.