Prosthesis-based techniques are the predominant form of breast reconstruction worldwide. The most performed surgical technique involves the placement of the expander in a partial submuscular plane. The coverage of the implant remains a difficult management problem that can lead to complications and poor outcomes. The use of the serratus fascia flap may be the best choice to create a subpectoral pocket for the placement of a tissue expander, with excellent results in terms of morbidity and cost-effectiveness. A total of 20 breast reconstructions with the inferolateral coverage with the serratus fascia were performed. Patients demonstrated a low overall complication rate (9.5%), such as seroma and infection, with complete resolution during the follow-up and no major complications. The US examination of the soft tissues over the implant reported thickness measurements that demonstrated a good coverage over the inferolateral area. Our study shows that using the serratus fascia flap to create a pocket with the pectoralis major for the placement of the tissue expander is an effective technique during two-stage breast reconstruction. The resulting low rate of morbidity and the US findings collected reveal the safety of this procedure. Its success relies on appropriate patient selection and specific intraoperative technique principles.