The electrical properties of [La(1-x)Mx]-P3O9 metaphosphate glasses, where M is Ba, Sr, Ca, and 0 <= x <= 0.8 were investigated in the 300-500 degrees C range. The protonic conductivity increases two orders of magnitude from the unsubstituted to the 60% substituted glass reaching a maximum conductivity of about 10(-5) S/cm at 450 degrees C. The activation energy is found to be approximately independent of concentration though dependent on the type of modifying substitutional cation, and decreases from about 1.04 eV for Ca and Sr to similar to 0.96 eV for Ba. AC impedance measurements were used to find the DC ionic conductivities. Mean ion travel distances at the frequencies, nu(center dot)(Z) or nu(center dot)(M), associated with the maximum in Z(n) or M-n were found to be up to 30 times larger than the average oxygen spacing in the glasses. While diffusion coefficients derived from conductivities, D-sigma, were vastly lower than an uncorrelated diffusion coefficient computed from first principles, the travel distance at nu(center dot)(Z) or nu(center dot)(Z) derived from a simple random walk expression using D-r, was surprisingly close to those derived from the more rigorous statistical treatments. The ratio xi=D-sigma/D-r << 1 may be interpreted as indicative of highly correlated ion motion and strongly reduced mean attempt frequencies, together with a mean activation energy for motion increased by Delta E=E-sigma-E-r over that of the uncorrelated intertetrahedral motion of an ideal crystal characterized by D-r. (C) 2010 Elsevier B.V. All rights reserved.