Studies have been made to state the influence of dual beam configuration on porosity formation. Welding experiments were carried out on two aluminum alloys, extremely sensitive to porosity formation under laser beam. The results show that the bispot configuration reduces drastically the porosity rate. Indeed, the use of dual beam conditions ensures a larger and more stable weld pool that allows the porosity's ejection. This has been observed by a high speed CMOS camera, which has followed the fluctuations of the keyhole, and has given the approximate melting pool dimensions in single and dual beam configurations, for several welding speed and beam distances. We have already observed an evolution of the weld pool geometry, which tends to stabilize the melt pool flow, providing free of porosity beads with a stable bead aspect. Indeed, the bead surface is smoothed, and a regular chevron welded structure is built during solidification. After all, we tried to set up a correspondence between the oscillations of the keyhole, the melt flow examined, the geometry of the weld pool achieved upon the bead aspects obtained, and the good metallurgical quality reached in dual beam arrangement.