Natrium Super Ionic Conductor (NaSICON) is one of the most promising solid electrolytes due to high ionic conductivity at room temperature, thermal stability, and good mechanical strength. In addition, the demand for long-lasting, cost-effective, and safer solid-state batteries has increased drastically which makes it even more attractive. However, the state-of-art developments have been impeded due to the lack of sustainable solid-electrolyte materials. Furthermore, no manufacturing method is available today to fabricate ultra-high purity yet fully dense NaSICON at low cost. In this study, we demonstrate, for the very first time that cerium-doped NaSICON (Na3Zr1.9Ce0.1Si2PO12) with relative density higher than 97% can be manufactured through one mechanical-activation-enhanced-process and one high temperature reaction. The powder processing, sintering condition as well as the ionic conductivity will be discussed.