Purpose: The aim of this study was to evaluate the long-term surgical and oncological outcomes after transanal total mesorectal excision (TaTME) for rectal cancer during an implementation phase on a national level. Method: This is a retrospective review of prospectively recorded data. Registration was initiated by the Danish Colorectal Cancer Group in order to assess the quality of care during the implementation of TaTME in Denmark. Data from four centers were pooled for simultaneous analysis. Short-term data was available from a prior study, and long-term data regarding recurrences, chemotherapy, and mortality was collected. Results: From August 2016 to April 2019, 115 TaTME procedures were registered. Patients were predominantly male (n = 85, 74%) with mid-rectal (n = 88, 77%) tumors. The overall local recurrence rate was 7.8% (n = 9) of which six patients also had systemic recurrence. Mean long-term follow-up was 59.4 months, and median time to local recurrence was 24.9 months. Local recurrences occurred predominantly among initial implementation cases. The overall mortality rate was 13% (n = 15). Of the 17 patients with recurrence, 35% (n = 6) died and developed either solely distant recurrence (n = 2, 12%) or in combination with local recurrence (n = 4, 24%). Conclusion: We found acceptable long-term oncological results after TaTME during the implementation phase in Denmark. There was an accumulation of local recurrences in the early phase of the study which emphasizes the importance of thorough training and proctoring when starting the approach.