Prosthetic technological advancements have significantly improved amputees’ quality of life, especially in enabling participation in high-impact sports. This study focuses on the design and fabrication of 3D-printed prosthetic running blades by incorporating lattice core sandwich structure design. The main goal is to enhance the mechanical characteristics of prosthetic blades to maximize durability and performance while reducing material consumption and production costs. The proposed procedure involved fabricating lattice core sandwich structures for the prosthetic blades utilizing rapid manufacturing techniques, notably Fused Deposition Modelling (FDM) of 3D printing. High-performance carbon fiber filaments like OBSIDIAN PA6 + CF, CARBON PA12 + CF, and eSUN ePA12-CF were identified as appropriate materials due to their superior mechanical properties. Furthermore, a PLA prototype was created to assess the lattice core sandwich structure’s production potential using 3D printing technology, demonstrating high accuracy and validating the design process. Preliminary research indicated that the 3D-printed prosthetic blades with lattice core sandwich structures offer notable gains in weight reduction and mechanical strength. The novel lattice architecture has provided an improved energy return and impact absorption, which are crucial for athletic performance. Additionally, the transition from traditional production techniques such as lamination, moulding and machining to 3D printing resulted in a 50% decrease in costs, and the lattice core architecture is used less material to create a lightweight yet strong structure. By incorporating lattice core sandwich designs, significant mass reductions can also be achieved. The study has concluded that the performance and reliability of 3D-printed prosthetic running blades are greatly enhanced by integrating lattice core sandwich constructions by combining cutting-edge manufacturing technologies with innovative design techniques. Future research is aimed to focus on refining the lattice design for various sporting needs and exploring the use of other high-performance materials to further improve the functionality and comfort of prosthetic devices.