(1) Purpose: The management of melanonychia is highly controversial. With growing melanonychia, in case of doubt, the entire lesion should be examined. It may appear similar to nail melanoma or may turn into melanoma. Here, we present surgical cases of nail bed total removal and free flap reconstruction. (2) Methods: Between 1 January 2020 and 31 December 2022, eleven patients were operated on for growing melanonychia, involving the hand and foot. After complete resection of the nail root and plate, immediate reconstruction was performed using a fasciocutaneous free flap. The authors describe the procedures in detail with a few illustrations and clinical photographs depicting the techniques. (3) Results: All patients underwent complete nail unit removal around the anatomic boundaries of the nail. Histology showed a nevus and no malignancy in all cases. We used three onychocutaneous flaps, three hypothenar flaps and five venous flaps. All flaps survived, with one case of partial necrosis which spontaneously healed with secondary intention. In the follow-up periods, there was no recurrence or nail regrowth. (4) Conclusions: These free flap techniques are very useful for total nail bed defect reconstruction after melanonychia lesion total ablation.