It has been reported that the properties of a foam-based sandwich panel can be enhanced by incorporating nanoclay into the facesheet or foam core. In this study, an attempt was made to disperse nanoclay into the epoxy adhesive so as to bond the facesheet with the core. The sandwich panel in this study was fabricated using a basalt/epoxy laminate as the facesheet and polyvinyl chloride foam as the core material. The characterisation results through flexural and quasi-static indentation tests revealed that the infusion of nanoclay led to an increase of up to 34% in the bending strength, 51% in the core shear strength, and 72% in energy absorption. In addition, the nanoclay-reinforced sandwich panel showed a slightly higher sound absorption coefficient than the control specimen without nanoclay. Another interesting observation from the flexural and quasi-static indentation tests was that the addition of nanoclay also influenced the failure behaviour and the size of the damaged area. The superior energy and sound absorption characteristics make the foam-based sandwich panel a potential material for structural applications requiring acoustic insulation.