In this study, a methodology for 3D printing of Silica (SiO2) structures for potential gas separation applications (either as membranes or as substrates for selective layers deposition) utilizing Stereolithography (SLA) is presented. The porosity, morphology and crystallinity of the 3D printed samples structure were optimized by the parametric study of the calcination profile of the printed ceramic SiO2 resin; the printed material was calcined at 450, 600 and 1250 °C by different residence times at different temperature steps. The microstructure of the 3D printed samples was characterized with Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Spectroscopy (EDS). Structural characterization (crystallinity and average crystal size) was performed by X-Ray Diffraction (XRD). The porosity and the specific surface area of the 3D printed samples were determined through the Brunauer–Emmett–Teller (BET) technique, which revealed that the surface area was gradually increased by increasing final calcination temperature. Permeability tests with flat sheet printed samples were performed in a constant pressure (isobaric) gas permeation system to quantify pure gases’ (e.g., CO2, N2, O2, Ar) permeances. Permselectivities of binary gaseous mixtures were obtained for printed samples calcined under different temperature profiles. The outcomes open new opportunities in 3D printing of versatile ceramic structures which can be exploited either as substrates for gas separation ceramic membranes or as membrane contactors for gas–liquid applications.