Increasing wettability of carbon felts is an important strategy to improve their efficiency in bio‐electrochemical applications. Herein, influence of cold remote plasma (N2 + O2) treatment on surface properties of carbon felts with poly(3,4‐ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) coating was tested, aiming to improve immobilizing of glucose oxidase enzyme (GOx). Spectra of N 1s and O 1s confirmed the integration of carbonyl and ether as well as amide and amine groups on bare carbon fiber surface, while on coated fibers, carbonyl groups were pre‐dominant. S 2p spectra confirmed oxidation of PEDOT:PSS coating with reduction of (S−) compared to (SO3−) group. GOx immobilized on different samples showed highest activity for PEDOT:PSS coating subjected to plasma with 2% O2, maintaining up to 60% after immobilization, and 37% of its activity after six cycles for some samples. Enzymes immobilized on samples without plasma treatment lost their activity after four cycles.