Semiconductor devices with a conformal coating in contact with a ground plane at a bottom side of the semiconductor devices and associated systems and methods are disclosed herein. In one embodiment, a semiconductor device includes a semiconductor die coupled to a first surface of a package substrate. The semiconductor device can also include a molded material covering at least a portion of the package substrate and the semiconductor die. The semiconductor device can also include a ground plane in the package substrate and exposed through an opening in a second surface of the package substrate opposite the first surface. The semiconductor device can also include a conformal coating coupled to the ground plane through the opening that can shield the semiconductor device from electromagnetic interference.