Background The incidence of early-onset colorectal cancer (EOCRC), has been rising in many countries for the past few decades, including in Aotearoa New Zealand. The aim of this study was to determine recent trends in EOCRC incidence and likely trends for the future. Methods The national cancer registry was used to identify cases of CRC in AoNZ from 2000-2020. We analyzed the trends in incidence of CRC by age, sex, and ethnicity and used this to make projections to 2040. Results Overall age-standardized incidence rate of CRC decreased from 61.0 to 47.3 cases per 100,000 (P=8.2x10-80). In those under 50 years, the incidence increased on average by 26% per decade (incidence rate ratio (IRR) 1.26, p=<0.0001), while for those aged 50-79 years it decreased (IRR 0.82, p=<0.0005), with no overall change in those over 80 years. Māori, have had a significant increase in overall incidence (IRR 1.28, p=<0.0005) driven by significant increases in EOCRC (IRR1.36, p=<0.0005). By 2040, we predict the incidence of EOCRC will have risen from 8.00 to 14.9 per 100,000 (6.33 to 10.00 per 100,000 in Māori). However, due to the aging population we estimate 43.0% of all CRC cases will be diagnosed in those over 80. Conclusion The incidence of EOCRC in AoNZ continues to climb with greater rises seen in Māori. The impact however of an ageing population, will see CRC in the elderly continue to dominate case numbers.