Various ¹⁰⁹Ag NMR techniques are used to study silver diffusion in silver iodide/silver phosphate glasses. In particular, for the first time, four-dimensional (4D) NMR is applied on solid ion conductors. All experiments consistently show that silver dynamics are governed by a very broad, continuous distribution of correlation times G(lg τ). First, over a wide temperature range, the ¹⁰⁹Ag NMR spectra are well described by a weighted superposition of a rigid-limit spectrum and a motionally narrowed line resulting from the slow and the fast silver ions, respectively. Further, very stretched ¹⁰⁹Ag NMR two-time correlation functions are observed where a lack of correlation for t → ∞ indicates that there are no truly immobile silver ions. When fitting the decays to a Kohlrausch function, exp(−(t/τ)^β), the stretching parameter amounts to β ≈ 0.2 and the mean correlation times 〈τ〉 show activation energies consistent with those reported for the dc conductivity. Finally, in 4D ¹⁰⁹Ag NMR echo experiments, the existence of dynamical heterogeneities is proven by the selection of a subensemble of silver ions with a dynamical behavior different from the ensemble average. In addition, the information content of multi-dimensional NMR experiments on solid ion conductors is visualized by model simulations.