Zirconia-based ceramics find wide application in engineering due to their very high hardness, resistance to elevated temperatures, and high fracture toughness. Among stabilizers of the advantageous tetragonal zirconia phase, yttria allows for better grain size refinement than ceria does; thus, Y2O3 is the most widely used. In the present study, comparative analysis was performed for yttria-stabilized zirconia (YSZ) and ceria-stabilized zirconia (CSZ) in terms of sinterability, densification, and mechanical properties, including hardness and resistance to plastic deformation. The results proved that CSZ sintered in similar conditions as YSZ exhibits similar properties, including an elastic modulus of 200–220 GPa and H/E of 0.070–0.076. In particular, the hardness of the ZrO2–5 wt% CeO2 ceramic appeared to be 14.6 ± 0.5 GPa, close to that of ZrO2–3 wt% Y2O3, which was 14.20 ± 0.74 GPa. However, SiC addition to ZrO2–5 wt% CeO2 composites increased hardness substantially up to 16.8 ± 0.8 GPa. Moreover, the fracture toughness of CSZ was 2.5 times higher than that of YSZ sintered under identical conditions. Thus, CeO2 can be a good, cheaper alternative to the traditionally used Y2O3 stabilizer for submicron-grained tetragonal zirconia ceramics.