The substitution series Li3-xIn1-xZr xCl6 (x=[0 -0.5], steps of 0.1) was synthesised, resulting in a maximal ionic conductivity at x=0.3 of 2.02 mS/cm at room temperature. Correlations between the structural models, derived from combined refinement of the x-ray and neutron diffraction, and the hopping processes, probed by solid-state NMR, reveal a complex diffusion mechanism. The authors would like to highlight the importance of measuring both neutron and