LiSn2P3 - y V (y) O-12 powders with y = 0.2, 0.4, 0.6, and 0.8 are prepared by mechanochemical milling method. The pellets of the compounds are heat treated at temperatures between 700 to 1,000 A degrees C for sintering period of 8 h. X-ray diffraction analysis indicates that all samples consist of rhombohedral crystalline LiSn2P3O12 phase. Energy dispersive X-ray analysis confirmed that V5+ has been successfully substituted into LiSn2P3O12 crystalline phase. The conductivities of the pellets are determined using impedance spectroscopy. Impedance analysis shows enhancement in both bulk and grain boundary conductivities with increase in y. The enhancement in bulk conductivity is due to decrease in bulk activation energy reflecting an increase in ion mobility as a result of an increase in bottleneck size. Enhancement in grain boundary conductivity is attributed to increase in the number of conducting pathways due to an increase in crystallite homogeneity.