To aid in advancing the functionality of bioplastics, co-injection moulding was investigated as a means to combine two biodegradable polymers: brittle, sugar-based polylactic acid (PLA) and tough polycaprolactone (PCL)..Procedural development reviewed the influence of injection speed, melt temperature, and content ratio on part formation in a complex mould geometry.Co-injected specimens were mechanically compared with equivalent blends according to mass-based content ratios; tensile, flexural, and impact properties were evaluated..The layered sandwich morphology produced parts with balanced mechanical properties that had greater strength and stiffness compared to blends and were tougher than neat PLA.These findings could help make these greener alternative materials more commercially viable and lead to reduced petroleum resource consumption and less landfill waste.