Background/Objectives: Transforaminal endoscopic lumbar discectomy (TELD) under local anesthesia is a promising minimally invasive surgical option for intractable lumbar disc herniation (LDH). However, our understanding of access pain prediction during foraminal pathological procedures is limited. To our knowledge, no predictive rules for access pain during TELD have been established for foraminal or extraforaminal LDH. This study, with its potential to predict access pain during TELD and to discuss strategies for pain prevention and management, could significantly impact the field of endoscopic spine surgery. Methods: This observational study included 73 consecutive patients who underwent TELD for foraminal or extraforaminal LDH between January 2017 and December 2022. Preoperative clinical and radiographic factors affecting significant access pain and the impact of access pain on clinical outcomes were evaluated. Results: The rate of significant access pain was 13.70% (10 of 73 patients). Extraforaminal LDH tended to cause more severe pain than foraminal LDH during TELD under local anesthesia (p < 0.05). Although the degree of access pain was not related to global outcomes, increased pain was strongly associated with a prolonged operative time and length of hospital stay (p < 0.05). Conclusions: TELD can be an effective surgical option for foraminal or extraforaminal LDH under local anesthesia. More access pain may develop during TELD for extraforaminal LDH. The extraforaminal component of LDH can narrow the safety working zone. Significant access pain may prolong the duration of surgery and hospitalization. Thus, a specialized technique is required for the clinical success of TELD.