The sixth season of La Voz Kids premiered on 7 May 2021 on Antena 3.
David Bisbal, Rosario Flores, Vanesa Martín and Melendi remained as the coaches of the show.
Eva González and Juanra Bonet also returned for their second season as hosts.
Contestants who won their battle or were stolen by another coach advanced to the Knockouts.
Known as "El Ultimo Asalto" in Spanish, in this round each teams' six participants perform, and the coaches select only four to advance for the semi-final.