This study aimed to investigate the effects of plasma-activated water (PAW) combined with a chitosan–oregano essential oil (CS-OEO) coating on the physicochemical, microbiological, and sensory attributes of carp fillets during chilled storage. Fresh carp fillets were immersed in sterile deionized water, PAW, CS-OEO, and PAW+CS-OEO, respectively, and stored at 4 °C for 10 d. The results showed that plasma-activated water combined with chitosan–oregano essential oil could effectively inhibit the microbial growth in carp fillets during chilled storage. At 10 d storage, the total viable count of carp fillets treated with PAW+CS-OEO decreased by 2.87 log10 CFU/g when compared to the control. The lowest pH values were found in the carp fillet samples after the PAW+CS-OEO treatment; as well, the carp fillet samples after the PAW+CS-OEO treatment showed the lowest total volatile basic nitrogen, thiobarbituric acid reactive substance values, and K values. In addition, the carp fillets in the PAW+CS-OEO treatment group showed the smallest color changes and the highest scores in sensory properties during chilled storage. This study provides a basis for the potential application of plasma-activated water combined with chitosan–oregano essential oil in the preservation of carp fillets and contributes to developing a new food packaging.