A semiconductor package includes a circuit board structure, a redistribution layer structure, a package structure, and a ring structure. The redistribution layer structure has a first region and a second region surrounding the first region. The redistribution layer structure is disposed over and electrically connected to the circuit board structure. A metal density in the second region is greater than a metal density in the first region. The package structure is disposed over the first region of the redistribution layer structure. The package structure is electrically connected to the redistribution layer structure. The ring structure is disposed over the second region of the redistribution layer structure.