<p>In the realm of lithium superionic conductors, pursuing higher ionic conductivity is imperative, with the variance in lithium-ion concentration playing a determining role. Due to the permanent and temporary site-blocking effects, especially at non-dilute concentrations, not all Li-ions contribute to ionic conductivity. Here, we propose a strategy to directly calculate effective mobile ion concentration in which multiple-ion correlated migration is considered in the percolation analysis with the input of Li-ion distributions and hopping behavior based on kinetic Monte Carlo simulation, termed P-KMC. We provide examples of two representative lithium superionic conductors, cubic garnet-type Li_<i>x</i><i>A</i>₃<i>B</i>₂O₁₂ (0 ≤ <i>x</i> ≤ 9; <i>A</i> and <i>B</i> represent different cations) and perovskite-type Li_<i>x</i>La_{2/3−<i>x</i>/3}TiO₃ (0 ≤ <i>x</i> ≤ 0.5), to demonstrate the direct dependence of the ionic conductivity on the effective mobile ion concentration. This methodology provides a robust tool to identify the optimal compositions for the highest ionic conductivity in superionic conductors.</p>