Colorectal cancer (CRC) is a leading cause of cancer-related morbidity and mortality in New Zealand, with the Southland region having the second highest incidence nationally. The National Bowel Screening Programme (NBSP) was rolled out in April 2018 with the aim of improving colorectal cancer outcomes through early detection. This study evaluates the impact of the NBSP on presentation patterns, surgical outcomes, and staging of CRC cases at Southland Hospital, within the first five years of implementation. We conducted a retrospective cohort study of patients diagnosed with CRC between April 2013 and March 2024. The pre-NBSP cohort (April 2013–March 2018) was compared with the post-NBSP cohort (April 2018–March 2024). Clinical, pathological, and operative data were extracted from hospital records and cancer databases. The primary outcome was the proportion of patients presenting acutely versus electively. Secondary outcomes included cancer stage at diagnosis, post-operative complication rate (Clavien-Dindo grade ≥3), length of hospital stay, and overall survival. The introduction of the NBSP has resulted in a substantial increase in early-stage CRC detection. Screen-detected patients had lower median stage, shorter post-operative length of stay, fewer complications, and improved survival, though not all differences were statistically significant. These findings suggest a significant reduction in healthcare burden and improved patient outcomes in the target population following NBSP implementation. However, a notable proportion of CRC cases occurred in the under 60 age indicating missed opportunities for earlier detection. This study provides real-world evidence on the early effectiveness of population-based CRC screening in a regional setting. Our findings support the more recent decision to broaden the NBSP inclusion age, and suggest that a further reduction of the screening age should be considered.