Zinc electroplated mild steels have been used extensively in automotive, marine and petrochemical industries. However, their vulnerability to corrosion and structural failure over time has required the inclusion of metallic oxide to enhance the coating properties. This work examined the influence of time variation on the corrosion response and microstructure of Zn-MgO-Al2O3 electroplated mild steel. The corrosion properties of the coating were examined using the potentiodynamic polarization experiment in a three-electrode system, employing a 3.5% wt. NaCl solution. The microstructure of the coated samples was examined using the Scanning Electron Microscope (SEM). The control (uncoated sample) exhibited the least corrosion resistance, with the corrosion rate (Cr) and corrosion current density (jocorr) of 20.707 mm/year and 1782 μA/cm2, respectively. The steel coated with Zn-MgO30-Al2O3 (20 mins) exhibited the optimum corrosion resistance, with the Cr and jcorr of 1.0521 mm/year and 90.51 μA/cm2, respectively. The foregoing indicated that the coating minimized the attack on the steel surface by the corrosive medium. The SEM images indicated that the coatings were well dispersed on the steel surface, exhibiting minimal cracks and pores, revealing that the coating constituents are compatible. The variation in the deposition time and mass concentration of MgO had a significant effect on corrosion resistance and the microstructure of the coatings. Hence, the coating could be employed for advanced applications such as automotive, marine, petrochemical and chemical storage.