In this study, a comparative investigation of the subwavelength transmission properties of graphene- and metal-coated nanowires is conducted. By using the finite element method, the modal field distribution and transmission properties of the lowest-order modes are investigated based on the frequency and structural dimensions for single nanowires and nanowire dimers. The results showed that when the thickness of the metal layer is larger than the skin-depth, graphene-coated nanowires exhibit better fundamental modal field confinement. However, when the thickness of the metal layer is far smaller than the skin-depth, the subwavelength transmission properties of the metal-coated nanowires are comparable to those of graphene-coated nanowires. These results will provide a reference for choosing plasmonic materials and have potential applications in subwavelength photonic devices.