In patients with severe, long-standing carpal tunnel syndrome and thenar muscle atrophy, nerve decompression alone is unlikely to restore thumb opposition. A multitude of tendon transfer techniques have been described to restore thumb opposition. We describe the technique of an endoscopic carpal tunnel release with opponensplasty using ring finger flexor digitorum superficialis (FDS) tendon under Wide Awake Local Anaesthesia No Tourniquet (WALANT) and ultrasound assistance.