This study investigated the effect of welding current during gas metal arc welding (GMAW) on the microstructure and composition of an Al 5083 alloy. As the welding current increased from 650 to 950 A, several changes were observed in the heat-affected zone (HAZ): grain coarsening and the formation of liquation cracks, and in the weld zone (WZ): increasing average secondary arm spacing and Mg loss. Therefore, the welding currents above 800 A are likely to cause liquation cracks in the HAZ and deterioration of the alloy's mechanical properties. Thus, welding condition with low heat input must be applied to improve the mechanical properties of the welds. This study provides a correlation between the weldability of Al 5083 alloy and welding current, offering a competitive advantage of liquid hydrogen storage containers.