Yttria-stabilized zirconia (YSZ) and calcia-stabilized zirconia (CSZ) were deposited on SR34 steel by electron beam physical vapor deposition (EB-PVD) as potential top piston ring coatings for internal combustion engines. The study aimed to enhance the surface, tribological, and tribocorrosion behavior of SR34 steel in extreme service environments. The deposited layers were characterized for microstructure, phase formation, surface roughness, microhardness, sliding wear, abrasion resistance, thermal expansion behavior, and tribocorrosion behavior. SEM/EDS analysis confirmed the formation of continuous, adherent ceramic coatings, with measured thicknesses of approximately 1.35 µm for the YSZ coating and 1.16 µm for the CSZ coating. The surface roughness decreased to 0.235 µm and 0.188 µm for YSZ and CSZ, respectively, compared with 0.274 µm for the uncoated SR34. The coatings had significantly higher microhardness (614.54 HV for CSZ and 668.54 HV for YSZ) than the 390.4 HV substrate, with YSZ showing the highest hardness. Pin-on-disk tests on cast iron showed that both coating types significantly reduced wear loss, wear rate, and coefficient of friction relative to the uncoated substrate, with CSZ demonstrating the best overall sliding wear behavior. Abrasion tests indicated good adhesion and coating integrity, and thermal expansion tests indicated that the two coatings were thermally compatible with SR34 steel. Tribocorrosion testing also showed that the two coatings were more resistant to wear and electrochemical degradation when used together, with CSZ showing the most consistent overall behavior. Overall, both coatings improved SR34 performance, but CSZ showed the most consistent behavior in piston rings.