Molecular dynamics investigations suggest the significance of Si/P ordering on the nature of ion transport in NASICONs (acronym for Na-superionic conductor). For certain Si/P ordering predominantly two dimensional transport of Na+ ions in Na2Zr2SiP2O12 is predicted, which is otherwise known to be an isotropic ionic conductor. The microscopic energetic barriers and topology of the conduction channels are analyzed. (C) 2013 Elsevier B.V. All rights reserved.