This work is a preliminary study investigating the issues related to the preparation and characterisation of green composites with a biodegradable matrix (PLA) and a natural filler typical of the Mediterranean area, sourced from alien/invasive plants (Chamaerops humilis). Additive manufacturing has been chosen as the primary technique to produce these bio-composites, leveraging its ability to produce complex geometries with precision. The choice of Chamaerops humilis is motivated by the fact that these plants are non-edible and abundant in the Mediterranean area, aligning with the new design guidelines inspired by the circular economy and “zero waste” principles. This paves the way for the creation of a new generation of green and sustainable materials. Using this plant as a filler for green composites is expected to enable the biodegradation of the composites in marine environments while providing remarkable mechanical properties. Starting from the selected materials, filaments will be manufactured for 3D printing components made of polymeric material with different filler percentages (10% wt and 20% wt). Mechanical and chemical-physical analyses will be conducted to evaluate the process parameters and assess their printability. The effect of fillers and their different percentages on the mechanical performance of the filaments will also be evaluated.