Barrrio signed with KSW on October 31, 2020 and faced Mateusz Legierski at KSW 56: Polska vs. Chorwacja on November 14, 2020. He lost the fight via majority decision. His second fight with KSW came at KSW 58: Kołecki vs. Zawada, when he faced Bartłomiej Kopera. Barrio won the fight by unanimous decision.
