Various embodiments for molding tools for moisture-resistant image sensor packaging structures and methods of assembly are disclosed. Image sensor packages of the present invention include an interposer, a housing structure formed on the interposer for surrounding an image sensor chip, and a transparent cover. The housing structure may cover substantially all of the interposer chip surface. In another embodiment, the housing structure also covers substantially all of the interposer edge surfaces. The housing structure may also cover substantially all of the interposer attachment surface. An image sensor chip is electrically connected to the interposer with sealed wire bond connections or with sealed flip-chip connections. The housing structure may include runners that enable simultaneous sealing of the interior of the image sensor package and of the transparent cover.