Fused deposition modelling (FDM) has recently attracted much attention in developing polymer-based composites in different fields. The mechanical behaviour of any polymer composite needs to be understood for the particular applications. In the present work, bio-ceramic (alumina and Yttria stabilized zirconia (YSZ)) filled polylactic acid filament was developed. The developed bio-composites’ thermal and mechanical characterization (impact strength and hardness) were examined thoroughly by fabricating the specimens using FDM technique. The scanning electron microscope (SEM) has been used to investigate the fracture surface characteristics. It has been found that ceramic-reinforced PLA bio-composite filament was successfully developed. The thermal analysis showed no significant change in critical temperatures of bio-composites in comparison with PLA. The impact strength of PLA filled with alumina and zirconia has the highest value (2.19 kJ/m2) with 21.66% enhancement. The shore D hardness of PLA/alumina composite found to be the highest (71 shore D) is in comparison with all other composition due to remarkable hardness of alumina. It is worth mentioning that this work offers a guideline for developing composites with bio-ceramics to improve the mechanical capabilities of neat PLA in different applications including biomedical.