Garnet-like structures containing lithium are of interest for applications in lithium ion batteries because of their inherent lithium ion conductivity and stability against chemical reaction with Li. Here, a series of materials, with parent composition LaLi0.5Fe0.2O2.09, are synthesized using solid-state chemistry, and characterized, in terms of their structure, using a combination of powder X-ray diffraction (PXRD), 7Li, and 139La solid-state NMR, which reveal disorder on the Li and Fe sites in the lattice. The 7Li spectra comprise a set of peaks that are distinguished based on their T 1 relaxation properties, as a diamagnetic set and a paramagnetic set of peaks. The 139La spectra include two La environments, one well-defined, with a C Q of 56 MHz ± 1 MHz and asymmetry parameter, η of 0.05 ± 0.05, and a second, which experiences a range of local environments, because of the Li/Fe substitution, and has a C Q of 29 MHz ± 2 MHz, and η of 0.6 ± 0.1. The dynamics within the materials were characterized using impedance spectroscopy, and trends were correlated with the lithium content and structural features. The best conductivity was determined for the parent material, LaLi0.5Fe0.2O2.09, after sintering at 850 °C. The complex 7Li and 139La NMR spectra, interpreted together with (PXRD) data, indicate that the increasing concentration of lithium in the material populates an iron site with excess lithium, in a range of possible local environments, which appears to decrease the total ionic and electronic conductivity.