Purpose Early onset colorectal cancer (EoCRC), commonly defined as colorectal cancer diagnosed in people under 50 years of age, is increasing in incidence in Australia and New Zealand. The cause of this remains unclear. Despite relatively small populations, the magnitude of this increasing incidence is among the highest in the world and insights obtained locally could have potential global impact. No review has focused exclusively on the evidence base in Australia and New Zealand. The objective of this scoping review was to comprehensively map and synthesise the literature for EoCRC across Australia and New Zealand, focusing on themes and data sources. Methodology A scoping review was performed according to the PRISMA guidance. Inclusion criteria: English language, humans, publications 01/01/200 – 31/05/2025, Australian and/or New Zealand patients, studies addressing EoCRC (adenocarcinoma). A systematic literature review was performed: 698 title and abstracts were screened, 72 full texts were reviewed, with 59 studies included for final analysis. The results were grouped by source of data and shared themes. Results Studies were mostly derived from national and state-based cancer registries and thus presented results achievable by analysis of these databases: incidence, patient demographics, familial cancer syndromes and genetics, tumour characteristics, treatment, short term outcomes and survival. Direct comparison between studies was difficult due to the heterogeneity of patient groups and outcome measures. Important gaps identified in the literature included lack of longitudinal risk factor analysis, detailed clinicopathological data comparisons and quality of life studies. Conclusion Australia and New Zealand benefit from the mandatory reporting of colon cancer into central registries, however, to further progress our understanding of EoCRC, prospectively collected and detailed clinicopathological data are required.