The effects of B2O3 addition on the properties of the Li1.5Al0.5Ge1.5(PO4)3 (LAGP) glass ceramic have been studied. The crystallization temperature of the LAGP decreases with the addition of B2O3. The glasses are crystallized at different temperatures and characterized for microstructure and ionic conductivity. The highest total conductivity of the glass ceramic material, 6.9 × 10−4 S cm−1 at 25 °C is achieved by crystallizing the glass at 825 °C for 5 h with the addition of 0.05 wt% B2O3. Non-linearity in Arrhenius plot is observed due to the characteristics of AlPO4 dielectric phase. In addition, the B2O3 added LAGP glass ceramic is stable in weak acidic and neutral solutions, but highly corroded in strong acidic and basic solutions.