Towards a sustainable energy model safer new generation energy storage devices with high energy density and power are needed. In this sense, the improvement in terms of efficiency and sustainability has led to the interest solid state batteries (SSBs).  Lately, sodium ion batteries (SIBs) due its abundance, low cost and improvements in terms of fast sodium-ion conductor solid electrolytes (SCSEs) have become an emerging alternative. Among all the SCSEs NASICON type electrolyte is one of the most well-known electrolytes, being widely developed in terms of synthesis and materials. However, the processing and manufacturing of these electrolytes has gone almost unnoticed, without considering that well-designed structures of electrodes/electrolytes are the bridge toward turning advanced energy materials into high-performance devices. This work presents the fabrication of complex 3D NASICON electrolytes by direct ink writing (DIW). Through a colloidal route fine NASICON phase powder with high pureness is obtained, empowering the obtaining of NASICON printed electrolytes in one step fabrication process. By means of the development of the ink, a dense electrolyte layer, acting as ionic conductor and separator, was inserted between two complex porous patterns with a total height below 1.2mm. Further, densification of the 3D electrolyte was analysed in order to improve the ionic conductivity and, therefore, the electrochemical performance of the electrolyte. Thus, fast ion conductor NASICON solid electrolyte with shorter diffusion pathways and have larger interfacial surface areas between electrode/electrolyte was obtained, enhancing the electrochemical properties by 3D layer-by-layer design.