Background: The COVID-19 pandemic has caused unprecedented health care challenges mandating surgical service reconfiguration. Within our hospital, emergency and elective streams were separated and self-contained Protected Elective Surgical Units were developed to mitigate against infection-related morbidity. Aims of this study were to determine the risk of COVID-19 transmission and mortality and whether the development of Protected Elective Surgical Units can result in significant reduction in risk. Methods: A retrospective observational study of consecutive patients from 18 specialties undergoing elective or emergency surgery under general, spinal, or epidural anaesthetic over a 12-month study period was undertaken. Primary outcome measures were 30-day postoperative COVID-19 transmission rate and mortality. Secondary adjusted analyses were performed to ascertain hospital and Protected Elective Surgical Unit transmission rates. Results: Between 15 March 2020 and 14 March 2021, 9,925 patients underwent surgery: 6,464 (65.1%) elective, 5,116 (51.5%) female, and median age 57 (39–70). A total of 69.5% of all procedures were performed in Protected Elective Surgical Units. Overall, 30-day postoperative COVID-19 transmission was 2.8% (3.4% emergency vs 1.2% elective P 70, male sex, American Society of Anesthesiologists grade >2, and emergency surgery were all independently associated with mortality. Conclusion: This study has demonstrated that Protected Elective Surgical Units can facilitate high-volume elective surgical services throughout peaks of the COVID-19 pandemic while minimising viral transmission and mortality. However, mortality risk associated with perioperative COVID-19 infection remains high.