Half a year after solution heat treatment (SHT) naturally-aged Al-Mg-Si alloy blanks are usually classified as expired, since a decrease of formability due to natural aging (NA) is expected. This decrease may affect the stability of the forming processes as well as the integrity of the formed components. Extending the period of stable formability is of high interest for the sheet metal forming industry; however, knowledge about the time-dependent deterioration of the formability is still lacking. Therefore, this work investigates the influence of NA on the formability of four dry-lubed 1-mm-thick Al-Mg-Si alloy blanks with different contents of Si and Mg. The formability-related material properties of the blanks were tested over a period of 18 months. Deep drawing experiments for characterizing the formability by using a cross-shaped tool as well as plate bending tests for characterizing the bendability were performed. After 18 months of NA, the yield strength of each of the investigated Al-Mg-Si alloy blanks increased by about 20-25 %, but uniform strain, fracture strain, anisotropy (r-value) and maximum drawing depth did not significantly change. Hence, the formability − as characterized by the maximum drawing depth − can be related to the r-value, since both were almost constant during NA. Moreover, a relationship between the bendability and the strain hardening behavior (n-value) was observed, since both continuously decreased during NA.