Background: The COVID-19 pandemic caused significant challenges to healthcare systems worldwide, necessitating the reallocation of medical resources and the implementation of infection-control precautions. These measures may have adversely affected the timely diagnosis and management of colorectal cancer (CRC) by delaying surveillance colonoscopies for CRC. Methods: A retrospective cohort study was conducted including patients who underwent Hartmann’s procedure and anterior resection for CRC at Lyell McEwin Hospital in South Australia, between 2018 and 2023. Results: A total of 119 patients were included in the study, of whom 57 underwent emergency Hartmann’s procedure and 62 underwent elective anterior resection. Tumour stage differed between groups (p < 0.001). No patients in the Hartmann’s group had T1 or T2 disease; 14 (24.6%) had T3 and 43 (75.4%) had T4 disease. In the anterior resection group, 20 (32.3%) had T1, 7 (11.3%) T2, 28 (45.2%) T3, and 7 (11.3%) T4 disease. Nodal involvement was more common in the Hartmann’s group (32 patients, 56.1%) compared with the anterior resection group (23 patients, 37.1%; p = 0.04). Subgroup analyses were performed for patients who underwent each operation across three distinct time periods: pre–COVID-19, during COVID-19, and post–COVID-19. There was an increase in emergency Hartmann’s procedures during the COVID-19 period (61%) compared with the pre–COVID-19 (37.5%) and post–COVID-19 (43.5%) periods. In parallel, the proportion of elective anterior resections decreased during the COVID-19 period (39%) compared with the pre–COVID-19 (62.5%) and post–COVID-19 (56.5%) periods. Conclusion: this study demonstrates an increase in the proportion of patients underwent emergency Hartmann’s procedures for CRC during the COVID-19 period, alongside a decrease in elective anterior resections compared with the pre- and post-COVID-19 periods. These findings raise concern regarding potential delays in diagnosis and underdiagnosis of CRC during the COVID-19 pandemic.