A semiconductor package is provided. The semiconductor package includes a package substrate having a first region and a second region defined between an edge of the package substrate and an edge of the first region. A semiconductor die is disposed on the package substrate in the first region. A three-dimensional (3D) antenna is disposed on the package substrate in the second region. The 3D antenna includes a planar structure portion and a bridge or wall structure portion. A molding compound encapsulates the semiconductor die and at least a portion of the 3D antenna. A conductive shielding element is inside the molding compound or partially covers the molding compound. A semiconductor package assembly having the semiconductor package is also provided.