Microalloying is thought to improve the performance of Al–Mg alloys commonly used in transport applications. The effect of Y addition (0–0.4%) on the microstructure, mechanical properties, and corrosion resistance of Al–9.2Mg–0.7Mn alloy is investigated for potential use in engineering applications. The generation of the β‐Al3Mg2 phase along the grain boundaries is suppressed in the as‐cast alloy due to the formation of the AlMgY ternary phase. The average intergranular corrosion mass loss of the alloy with 0.1% Y addition decreases about 53.1% almost at no expense of mechanical performance in the as‐rolled alloy after annealing. Moreover, the alloy with 0.1% Y addition shows the corrosion mass loss about 30.2% lower than the Y‐free alloy in the sensitized state. The enhanced corrosion resistance of the alloy can be ascribed to the reduced β‐Al3Mg2 precipitation along the grain boundaries associated with Y addition.