Abstract The deuteron magnetic resonance spectra of SnCl2·2D2O single crystals have been measured from 208 to 300 K in order to elucidate the static and dynamic structures of water molecules in connection with the phase transition occuring at 234 K. The deuteron quadrupole coupling constants (asymmetry parameters) were determined at 208 K for four non-equivalent water deuterons. These values are 194.2±0.3 (0.066±0.004), 193.2±0.5 (0.112±0.003), 223.3±0.4 (0.206±0.003), and 244.0±0.4 kHz (0.058±0.003), depending largely on the hydrogen-bond strength or the D···O distance. The deuteron arrangements deduced from the EFG tensors agreed well with the ordered structure reported by an earlier ND study. The dynamical process of deuterons responsible for the high-temperature disordered structure was analyzed with the aid of the ND results and was ascribed to a combination of the flip motion of water molecules about each two-fold axis and their rotational motion around each pseudo-three-fold axis.