Atmospheric pressure plasma polymerization represents a promising coating technology, addressing drawbacks of traditional processes (solvent use, multistep procedures, etc.) while enabling deposition of thin cross‐linked polymer layers with high contour fidelity. We address technological challenges with a novel plasma device that integrates multiple plasma source benefits and investigate the suitability of two plant‐based precursors, chia and tung oil, for plasma polymerization to hydrophobize glass and paper. Chia oil enables the deposition of thin, covalently bonded hydrophobic polymer layers. Such coatings have diverse applications especially inside the paper industry, where water repellents in the form of internal and surface sizing have always been an essential functionalization step. Using bio‐based precursors and reducing extra chemicals contributes to substituting fossil‐based or harmful substances.