Metallic foams can be classified into closed-cell and open-cell foams depending on the connectivity between the cells. Currently, the majority of metallic foams on the market are closed-cell aluminium foams. However, open-cell aluminium foams are more appropriate for some applications. In this work, we analyze the thermal and acoustic properties, sound absorption coefficient at normal incidence and static flow resistivity of aluminium foams manufactured by means of the infiltration process. We have produced aluminium foams with similar porosity but with three different cell diameters: 0.5, 1 and 2 mm. The results reveal the important role of the cell diameter in fixing the physical properties of these materials. The foams manufactured by the infiltration technique are characterized by a highly homogeneous structure and by a high sound absorption coefficient at low frequencies when they are backed by an air gap. Specifically, its thermal and acoustic properties make the 0.5 mm cell diameter aluminium foam a good candidate for applications in the construction sector, for example.