In this work, different configurations of bioactive CaP-based coatings, including dicalcium phosphate dehydrate (DCPD), octacalcium phosphate (OCP), and dual-layer DCPD OCP coatings, were applied to control the corrosion behaviour of pure Mg. The adhesion force results demonstrated that the DCPD coating provided a higher adhesion force to the Mg substrate than the OCP coating, indicating its potential to enhance the interface stability between the implant and tissue. The results from the potentiodynamic polarisation tests demonstrated a five-fold reduction in corrosion rate for DCPD-OCP-coated Mg compared to uncoated Mg. The incorporation of dual-layer CaP coatings leverages the synergistic advantages of each constituent, enhancing coating adhesion via the compact structure of the DCPD base layer and providing a hydrophilic surface (contact angle ≤ 15°) via the OCP layer. In subsequent research, a 3D-printed WE43 Mg alloy, considered commercially available and clinically utilised, was examined, and novel CaP-phosphoserine (PS) composite coatings were explored to overcome the challenge of low CaP coating adhesion on its surface. The incorporation of a PS enhanced coating adhesion, altered crystallinity, and improved degradation resistance to a five-fold. Among different molar ratio, OCP-PS-WE43 (1:2) exhibited lower corrosion rates and greater stability. In vitro studies revealed no cytotoxicity, with cell viability exceeding 100% in OCP-PS WE43 (1:2) specimen extracts after 72 hours. Moreover, the optimised coating composition developed through a wet chemistry approach was successfully translated from a regular geometric shape to an irregular porous wedge shape while maintaining physicochemical properties, coating uniformity, and improving corrosion resistance. Overall, this approach effectively enhanced the corrosion resistance of Mg-based orthopaedic implants, potentially making them more suitable for clinical applications.