The development of novel ceramics is pivotal for advanced technologies that demand lightweight, high-strength, high-temperature components. This study delves into 3D-printed ceramic structures crafted from a preceramic polymer derived from siloxane resins, with a primary focus on nano-reinforced ceramic composites. Our goal is to investigate the feasibility and mechanical properties of these ceramics, analyzing how printing parameters like layer exposure duration and thickness influence their characteristics. In this study, we assess composition, density, shrinkage behavior, and compression performance of polymer-derived SiOC ceramics with alumina or silicon nitride filler particles. We establish a direct relationship between cure depth and exposure time, crucial for optimizing printing parameters. Photorheology tests indicate rapid curing, making the formulations ideal for vat-photopolymerization printing. Thermogravimetric analysis reveals significant mass loss during pyrolysis, primarily associated with methane and aromatic hydrocarbons and SEM–EDX confirms the composition of the ceramics as SiOC. The lattice design influences shrinkage and density. Micro-CT scans showcase defect-free green-stage structures, with 10% relative density retaining shape post-pyrolysis compared to 40% structures with distortions and voids. Compression tests reveal varying fracture patterns, with Schwarz G 10% showing sequential fractures and Schwarz D 10% exhibiting a complex failure sequence. Remarkably, lower relative density structures, such as Schwarz G 10%, demonstrate higher specific energy absorption.