Foramen magnum decompression (FMD) is a standard neurosurgical procedure, typically utilized to treat Chiari malformation. The aim of this educational project was to develop and validate a low-cost FMD simulation training model. Mold-based methods were used to develop a prototype. Feasibility was tested during an FMD training session for 17 neurosurgery trainees. Face and content validity were assessed through a Likert Scale. The perceived training benefit was determined using the Physician Performance Diagnostic Inventory Scale (PPDIS). A total of 87.5% successfully removed the C1 arch, 81.3% successfully performed an FMD, and 68.8% avoided injury to the underlying structures. The model scored highly for visual and tactile realism. The median confidence rating on PPDIS significantly improved from early learner to competent. We demonstrate feasibility, content, and face validity. Furthermore, this is a low-cost, portable model that can be easily replicated and used for simulation training.