<p>Plantar fasciitis is a common musculoskeletal condition and a major cause of heel pain caused by repetitive mechanical stress on the plantar fascia. In this study, plantar fasciitis insoles based on a commercial wool insole (Comforthotic^® ¾ length insoles, Hapad, Inc., USA) were designed using 3D modeling and fabricated by fused deposition modeling (FDM). Three filaments, thermoplastic polyurethane (TPU), lightweight TPU (LW-TPU), and lightweight polylactic acid (LW-PLA), with different hardness values were used to identify the most suitable option for plantar pressure reduction. Filament properties were analyzed using DSC, rheology and morphology. The 3D printed insoles were analyzed in terms of morphology and compressive properties, while plantar pressure was evaluated under both static standing and walking conditions to assess pressure distribution. The results showed that 3D printed insoles reduced maximum plantar pressure compared to barefoot and wool insole conditions. LW-PLA exhibited favorable pressure redistribution, especially in the metatarsal and heel regions, under the tested conditions. However, because comfort, pain, and long-term wear outcomes were not evaluated, further clinical and wearability studies are required. Future studies will further optimize region-specific lattice structures and evaluate long-term wearability, comfort, pain, and functional outcomes.</p>