The electrochemical behaviour of aluminum (Al) alloys in seawater medium was investigated using potentiodynamic technique, complemented by Scanning Electron Microscopy (SEM) and EDAX. SEM was used to characterize the corroded surface and to observe the extent of corrosion attack on the Al alloys after tested in seawater. EDAX analysis was used to identify elements present on the specimen surface. The results indicate that influences of alloying elements present in the Al alloys play important role in the corrosion of Al alloys in seawater. The behaviour of Al alloys with addition of Zn, Sn, Cu and Si was greatly enhanced in terms of its potential and corrosion behaviour. Potential of Al with alloying elements reached value more negative than -0.9VSCE and showed active corrosion behaviour.