This paper addresses the impact penetration and perforation behaviour of sandwich panels having a low density core expanded polystyrene foam (EPS) bonded to two aluminum (6061-T6) face-sheets. The effects of foam and plate thicknesses on the impact energy absorption of sandwich panels were also investigated. The dynamic response of panels was analyzed using the explicit finite element method. The foam core material was modeled as a crushable foam material with ductile damage, and the metal face-sheets as Johnson-Cook (JC)material. The cohesive response of the adhesive interface was considered using cohesive zone model. The analyses showed that the impact energy, face-sheet and foam core thickness affected significantly failure modes, contact force levels and histories. The low-speed impact tests of the sandwich panels with different face-sheet and foam core thicknesses showed similar contact force histories, energy absorption ability and deformation modes to those of finite element analyses.