[1] Initially a fourth-choice goalkeeper at the start of 2014–15, Abad profited from Jacobo Sanz's departure and Nauzet Santana's serious injury, being promoted to Roberto's backup.

[2] On 16 November 2014 he played his first match as a professional, replacing the latter due to injury in a 0–2 away loss against UE Llagostera in the Segunda División championship.

On 23 August 2018, he was loaned to fellow second division side Córdoba CF,[6] and became a first-choice mainly due to the club's poor financial situation.

[9] On 26 July 2022, Carlos Abad joined Spanish team side Hércules Club de Fútbol on a two-year deal.

On May 5, 2024, Hércules CF was crowned champion of Group III of the Segunda Federación after defeating Lleida Esportiu at the Estadio José Rico Pérez, in front of more than 20,000 fans who witnessed a historic match for the club.