within their crystal lattice and low thermal expansion [3; 4; 5; 6; 7; 8; 9; 10; 11; 12; 13; 14; 15]. Such properties led to the early employment of NASICON ceramics in a variety of applications, which ranged from ion-exchange membranes to waste management and sensors [16; 17; 18; 19]. Apart from the above implementations, NASICON has recently seen a renewed interest in energy storage applications: a response to the growing concerns at the international level regarding escalating climate change driven by greenhouse gas emissions. The latter has dictated the imperative shift to clean and renewable energy sources (RES) as a replacement for fossil fuels. Since most RES suffer from intermittency issues (e.g., wind, solar, and tidal energy), cost-effective utility-scale energy storage installations are needed to balance the energy supply-demand budget, thus underlining the importance of flexible and reliable grid systems [20; 21; 22]. Current grid-scale battery systems rely on the fully developed lithium-ion technology; however, with lithium being limited as a natural resource and therefore having high cost, other ion-exchange systems are sought as viable replacements. A most promising candidate has been identified in the form of sodium due to its high availability and low cost, giving rise to Na-ion batteries and thus upgrading the importance of NASICON as a sodium-based ion-exchange electrolyte in such systems [23; 24; 25; 26; 27; 28; 29; 30; 31]. Even more recent R&D advancements have seen the use of NASICON as a solid electrolyte in seawater flow batteries. Still in its infancy, the concept has the potential of becoming a true game-changer in the field of energy storage and conversion, especially since the flow electrolyte component (i.e., seawater) may be supplied in unprecedentedly large volumes, which translates into unfettered scalability [32; 33; 34; 35; 36]. In light of such developments, we marshaled a thorough investigation of the archetypal Na\({}_{3}\)Zr\({}_{2}\)Si\({}_{2}\)PO\({}_{12}\) (where \(x=2\) in the Na\({}_{1+x}\)Zr\({}_{2}\)Si\({}_{x}\)P\({}_{3-x}\)O\({}_{12}\) formula) that represents the limit case below which ionic conductivity decreases [3; 4; 37; 38; 39]. The primary challenge arises in navigating through the multiple methods developed for NASICON synthesis, which vary from the conventional solid-state reaction (SSR) to sol-gel Pechini methods, and to laser and plasma deposition [40; 41; 42; 43; 44; 45]. The above also diverge to include variations for optimizing electrical properties, by either controlling the elemental composition (e.g., sodium content) or by optimizing the grain boundaries in the crystalline lattice [46; 47; 48; 49; 50; 51; 52; 53; 54; 55; 56]. Since our priority lies in gaining insights into the primary mechanisms underlying Na\({}^{+}\) mobility and ionic conductivity, we chose to focus on the conventional SSR method and its associated protocols for synthesizing the classic Na\({}_{3}\)Zr\({}_{2}\)Si\({}_{2}\)PO\({}_{12}\) system, while keeping the SSR protocol as straightforward as possible without elemental substitutions or additions. Thus, the work presented here can serve as a benchmark for further studies. In parallel, we also addressed secondary processing parameters of the synthesis protocol that are often overlooked in the available literature, but nevertheless have dramatic effects on the investigated properties such as the applied pressure levels needed to compact the synthesized powders into pellet form--a key process for both laboratory and industrial scale preparation of NASICON solid electrolytes. We reassess the analytical techniques encountered in the bulk of the relevant literature concerning ionic conductivity determination and reporting by revisiting the arguments introduced in earlier fundamental research pertaining to the classic NASICON system [8; 37], and then expanding the investigated parameter space of frequency and temperature to make use of the capabilities offered by broadband dielectric spectroscopy.