IMPORTANCE The vascular supply of anterolateral thigh (ALT) free flaps is variable, and the pedicle length and ability to capture perforators to the flap may be limited by the anatomic configuration. We describe the reasoning behind performing the auto flow-through procedure, as well as the steps to carry this procedure out. OBSERVATIONS A retrospective medical chart review was performed within our health care system database to identify patients in whom the auto flow-through technique was used during reconstruction with an ALT free flap. The auto flow-through technique was applied to 3 separate ALT free flaps to incorporate perforators from 2 separate vascular systems. This technique allowed for more robust vascularity of the flap and/or optimized pedicle length that would have otherwise necessitated vein grafts. All patients had successful ALT free flap reconstruction and went on to have good functional results. CONCLUSIONS AND RELEVANCE The auto flow-through technique is an adaptation of the flow-through flap, which allows for capture of vascular perforators from separate sources when this configuration is present in the ALT free flap. This technique is especially useful when operating in a vessel-depleted neck or when maximizing pedicle reach is necessary. This technique allows the ALT to be used in challenging reconstruction cases regardless of the vascular branching pattern of the pedicle. LEVEL OF EVIDENCE 4.