Nylon filament is a widely used thermoplastic material in extrusion-based 3D printing, favored for its strength, durability, and excellent printability. It enables the fabrication of parts with complex geometries, high design flexibility, and cost-effective production, making it ideal for both prototyping and functional components. However, one significant drawback of nylon is its hygroscopic nature—it readily absorbs moisture from the surrounding environment, often at a rapid rate. This moisture uptake can negatively impact the filament’s performance during printing, leading to poor surface finish, reduced mechanical strength, and altered thermal behavior in the final printed parts. To better understand the effects of moisture absorption, this study investigates the mechanical and thermal properties of nylon parts printed using filaments with varying levels of moisture content. The nylon filament was conditioned in a controlled humidity chamber for different durations to simulate moisture exposure over time. Specimens were then printed using these conditioned filaments, and a series of tests were performed to assess their mechanical integrity and thermal stability. By analyzing the test results, the study aims to establish a correlation between filament moisture content and part quality, offering valuable insights into the degradation mechanisms and guiding best practices for filament handling and storage in nylon 3D printing applications.