Intensive research is currently being conducted on WAAM (Wire Arc Additive Manufacturing) processes. Previous studies have demonstrated the impact of current parameters on altering the structure and properties of 316L stainless steel. However, there is a lack of comprehensive information in the literature regarding the influence of electrode extension length (contact to tube distance) on changes in the structure and geometry of parts made of 316L steel using the CMT (Cold Metal Transfer) method. This parameter was often assumed to be constant in research experiments. The study aimed to determine how the length of the electrode extension affects the geometric properties of steel walls produced in the WAAM CMT additive manufacturing process. The experiment used 316LSi stainless steel to build 3D structures in the shape of straight walls. The chosen shape of the parts yielded the most benefits for preparing samples from the resulting structures for destructive testing. The research demonstrated that the length of the electrode extension is a crucial parameter in the additive manufacturing process of structures using the WAAM method. Modifying the electrode extension length in the WAAM process with a CMT machine impacts the bead geometry and, consequently, the overall model geometry. A 6 mm increase in the electrode extension length resulted in a model that was over 8 mm taller, despite using the same number of layers.