A golf ball includes a core and a cover surrounding the core. The cover includes a first hemispherical half and a second hemispherical half that define a seam line therebetween and along an outer surface of the cover. The seam line is non-planar and includes an integral number of cycles of a repeating wave that oscillates along the outer surface of the cover. Each cycle of the repeating wave has a 2π radian phase, and an intermediate section is interleaved within the repeating wave at phase angles that are integral multiples of π. Each intermediate section has a straight surface profile along the outer spherical surface.