The rapid densification behavior of 8 mol% Y2O3-stabilized ZrO2 polycrystalline (8Y-SZP) powder compacts at the initial stage of pressure sintering (relative density () below 0.92) has been investigated using an electric current-activated/assisted sintering (ECAS) system. Data points corresponding to a fixed heating rate were extracted from the densification rate () versus ρ and versus temperature (T) curves. These curves were obtained experimentally by consolidation at a fixed current. Under fixed current ECAS, the heating rate () decreases continuously over sintering time. Using a quasi- constant heating rate (CHR) method, data points were extracted to plot vs. ρ, vs. T, and ρ vs. T curves at a fixed . The stress exponent (n), estimated from a log-log plot of grain size (d)-corrected /ρ and effective stress (σeff) at 1300–1400 K, shows an almost constant value of 1. In addition, the activation energy (Q) for rapid densification, estimated from an Arrhenius plot of d-corrected /ρ also shows an almost constant value of 350 kJ/mol, which is considerably lower than the previously reported value of the activation energy for Zr4+ lattice diffusion of about 440 kJ/mol. These results suggest that rapid densification of 8Y-SZP by ECAS seems to proceed by diffusional creep controlled by grain-boundary diffusion of Zr4+ ions.