Fuel cell is an electrochemical device that converts fuel into electricity. Polymer electrolyte membrane fuel cells (PEMFCs) have been used for ground transportation due to its high efficiency and zero carbon emission. When it comes to unmanned aerial vehicles (UAVs), PEMFCs can support much longer flight endurance than internal combustion engines and batteries do. However, a lightweight PEMFC stack is required in order to carry enough payload for UAVs. In this research, a lightweight fuel cell stack was developed and fabricated based on the Horizon fuel cell stack. The stack components, including end plates, bipolar plates, and interconnects were redesigned and fabricated to replace those heavy components. Additive manufacturing (3D printing) and electroplating were used to fabricate bipolar plates and interconnects, whereas the end plates were machined from Garolite XX plates. The fabricated lightweight PEMFC stacks were tested using a Scribner 850e Fuel Cell Test System. The lightweight stack assembled with six electroplated bipolar plates showed that the maximum power density estimated was 3.514 W/cm2 with 4.5 V and 1.6 A/cm2 conditions for 100 ml/min of H2. The same fuel cell stack tested at 200 ml/min and 300 ml/min showed higher maximum power densities than 100 ml/min. The presentation includes design and fabrication, performance characterization, weight reduction strategy, and future work.