In June 2012, he signed a new contract with the Costa Rican club C.S. Cartaginés. Pailós made his official debut for Cartaginés in the opening match in the Winter 2012, scoring his first official goal and the tie against Belén Siglo XXI. In the second game, Pailós scored his second goal with the club and that opened the scoring against San Carlos on the victory of Cartaginés 0-2, after a good left footed shot. His third goal for the club was against Carmelita, after an Eduardo Valverde center and Pailos score on header, for the 1-1. Pailos made his fourth goal, a penalty in the tie 1-1 against Herediano in the Clásico Provincial. In the second goal of Cartagines against Puntarenas, Pailos made a header assistance to Andres Lezcano for 2-1 after a throw in of Esteban Maitland. The fifth goal of Pailos in the club was also a penalty and the 3-1 against Puntarenas and was the 2500th goal in the history of the national championship at the stadium Fello Meza. On 7 November, Pailos Scored his sixth goal from the penalty spot against Herediano.