High-entropy alloys are a new class of materials consisting of at least five elements in an equiatomic or close to equiatomic ratio, which provides them with unique properties. Non-equiatomic high-entropy Fe-Co-Cr-Ni-Mn and Fe-Co-Cr-Ni-Al alloy coatings were applied to the 5083 alloy substrate using wire arc additive manufacturing and the cold metal transfer process. The structure, elemental composition, mechanical and tribological properties of coating / substrate systems were analyzed using modern methods of materials physics. The deposition of FeCoCrNiMn and FeCoNiCrAl HEA coatings on the surface of 5083 alloy was accompanied by the formation of gradients of elemental composition and mechanical properties. A transition layer with a thickness up to 450 μm was formed at the coating / substrate interface located at the coating-substrate boundary. The elemental composition gradient of the transition layer was studied, and a high level of chemical homogeneity of the coating was revealed. Alloying of the coating with substrate elements was observed. The alloying of the substrate with coating elements is accompanied by nonmonotonic changes of element composition in the 500 μm depth layer.