Catalytic wet air oxidation (CWAO) of phenolic compounds over three activated carbons (ACs) has been investigated in a semibatch autoclave to better understand the influence of AC properties on the efficiency and stability of CWAO. Phenol, 4-nitrophenol, 4-chlorophenol, and 4-hydroxybenzoic acid, as well as synthetic mixtures comprising two to four of the aforementioned molecules, have been chosen as model pollutants to evaluate synergy or competition effects. To this end, the amount of pollutant(s) (re)adsorbed on AC during a preliminary adsorption step, the pollutant conversion, and the mineralization yield obtained during CWAO as well as the AC stability upon recycling are compared for each case.