A semiconductor package including an ultra-thin redistribution structure, a semiconductor die, a first insulating encapsulant, a semiconductor chip stack, and a second insulating encapsulant is provided. The semiconductor die is disposed on and electrically coupled to the ultra-thin redistribution structure. The first insulating encapsulant is disposed on the ultra-thin redistribution structure and encapsulates the semiconductor die. The semiconductor chip stack is disposed on the first insulating encapsulant and electrically coupled to the ultra-thin redistribution structure. The second insulating encapsulant is disposed on the ultra-thin redistribution structure and encapsulates the semiconductor chip stack and the first insulating encapsulant. A manufacturing method of a semiconductor package is also provided.