A semiconductor package and a manufacturing method thereof are provided. The semiconductor package includes a photonic die, an encapsulant and a wave guide structure. The photonic die includes: a substrate, having a wave guide pattern formed at front surface; and a dielectric layer, covering the front surface of the substrate, and having an opening overlapped with an end portion of the wave guide pattern. The encapsulant laterally encapsulates the photonic die. The wave guide structure lies on the encapsulant and the photonic die, and extends into the opening of the dielectric layer, to be optically coupled to the wave guide pattern.