The high performance fluoride ion conductors α-PbSnF 4 and BaSnF 4 have been studied using X-ray diffraction, 119Sn Mössbauer spectroscopy, and EXAFS. X-ray diffraction shows the unit-cell is a tetragonally distorted fluorite-type, with ordering of the metals which results in a superstructure along the c axis. The SnK, Pb L 3, and Ba L 3 X-ray absorption spectra of α-PbSnF 4 and BaSnF 4 as well as model compounds (SnO, β-PbF 2, and BaF 2) have been recorded at 300 and 77 K. Analysis of the extended fine structure (EXAFS) of α-PbSnF 4 and BaSnF 4 indicates they have a similar local structure around the corresponding metal atoms with average nearest neighbor distances of R SnF = 2.08(3) Å, R PbF = 2.50(3) Å and R BaF = 2.67(2) Å. The good agreement between the PbF and BaF distances derived from EXAFS with diffraction results and ion pair estimates indicates that the Pb and Ba ions determine the close-packing arrangement of the crystal structure. EXAFS shows that the local structure is much better defined around Pb and Ba than around Sn. This and the weak temperature dependence of the SnK EXAFS indicates a lower rigidity of next-neighbor fluorine shells around Sn than around Pb or Ba. In the α-PbSnF 4 structural type, the metal M (Pb or Ba) is in an eightfold coordination site similar to the cubic coordination in the fluorite-type, whereas Sn is in a unique SnF 5E pseudooctahedral coordination, with the lone pair E being stereoactive and making the materials strongly anisotropic. This is confirmed by the large quadrupole splitting observed in Mössbauer spectroscopy, Δ = 1.52(2) mm/s for α-PbSnF 4 and 1.52(1) mm/s for BaSnF 4. The mobile fluoride ions are probably disordered and widely spread over conduction paths, and they remain disordered even at low temperature when their long range motion is frozen. The structural results are discussed in relationship to proposed mechanisms for ionic conduction in these materials.