<p>This study explores the mechanical behaviour of multilayer sandwich panels made of glass fibre-reinforced polymer (GFRP) face sheets and hybrid cores combining aluminium honeycomb and modified sinusoidal corrugated layers connected with aerospace-grade adhesive. Experimental investigations were carried out under full-face compressive loading utilizing a universal testing machine, and the relevant force-displacement responses were recorded for all specimens. Four core designs were created with different layering sequences, and their peak load, mean load, and energy absorption capacities were obtained. The results indicate that integrating corrugated layers within honeycomb cores greatly boosts deformation stability, allowing the panels to resist compressive load over greater displacement ranges. The honeycomb cores show the progressive crushing whereas the corrugated cores generally have shown global bending and collapse along with hinge formation in certain cases. The hybrid cores also have indentation due to localized loading by corrugated contact surfaces. The addition of corrugated layers has shown an overall improvement in the mechanical behaviour of composite sandwich panels and may be preferred over all corrugated sandwich panels.</p>