ABSTRACT Solid electrolytes are central to enabling safe, high‐energy solid‐state sodium batteries. While oxyhalide‐type conductors have rapidly advanced lithium‐based systems, their sodium analogues remain less understood and underdeveloped. This gap arises from their intrinsically amorphous nature, which obscures structure–transport relationships and limits rational design. Here, we elucidate the atomic‐scale origins of sodium‐ion conduction in the mixed‐anion series NaTaO x Cl 6–2 x using a c