In the context of protecting Mg‐based nano‐objects for potential hydrogen storage applications, the potential of C:H layer as a barrier polymer material deposited by the plasma‐enhanced chemical vapor deposition process is examined. Corrosion tests reveal (a) good barrier properties of the C:H layer and (b) suggest an increase in the internal stress with the power dissipated in the plasma. The latter is attributed to an increase in the cross‐linking density of the coatings accompanied by an increase in the stiffness as shown by nanoindentation measurements. Finally, for a given set of plasma parameters, Mg‐based nanowires were successfully enrobed by the C:H coatings as evidenced by scanning electron microscopy measurements.