An electroformed sheath for protecting an airfoil includes a sheath body and a mandrel insert is provided. The sheath body includes a leading edge. The sheath body includes a pressure side wall and an opposed suction side wall, which side walls meet at the leading edge and extend away from the leading edge to define a cavity between the side walls. The sheath body includes a head section between the leading edge and the cavity. The mandrel insert is positioned between the pressure side and suction side walls, and includes a generally wedge-shaped geometry. A method for protecting an airfoil includes: 1) securing a mandrel insert to a mandrel; 2) electroplating a sheath body onto the mandrel and the mandrel insert; 3) removing the mandrel from the sheath body so that a sheath cavity is defined within the sheath body; and 4) securing the airfoil within the sheath cavity.