INTRODUCTION: There are unmet mental health needs of depressed adolescents and young adults (AYAs) across the USA. Behavioural technology adequately integrated into clinical care delivery has potential to improve care access and efficiency. This multisite randomised controlled trial evaluates how a coach-enhanced digital cognitive behavioural intervention (dCBI) enhances usual care for depressed AYAs in paediatric practices with minority enriched samples. METHODS AND ANALYSIS: Participants (n=750) ages 16-22 who meet threshold criteria for depressive severity (Patient Health Questionnaire-9; PHQ-9 score 10-24) will be recruited through paediatric practices across three academic institutions (Boston, Pittsburgh and San Diego). Participants will be randomised to 12 weeks of dCBI+treatment as usual (TAU) (n=450) or TAU alone (n=300) in outpatient paediatric practices. Assessments will be completed at baseline, 6 weeks and 12 weeks with the primary outcome being improvement in clinician-rated and self-reported depressive severity (Childrens Depression Rating Scale-Revised and PHQ-9) and secondary outcomes being self-reported suicidal ideation (item 9 on PHQ-9), anxiety severity (Generalised Anxiety Disorder), general quality of life (Satisfaction with Life Scale) and general functioning (Childrens Global Assessment Scale). The study design is an intent-to-treat mixed effects regression with group, and covariates nested within the sites. ETHICS AND DISSEMINATION: All participants or their parent/guardian (under 18 years or unemancipated) will give informed consent to a study team member. All data are expected to be collected over 18 months. The Institutional Review Board (IRB) is a board at each institution in the United States that reviews and monitors research involving human subjects. IRB approval from the University of Pittsburgh was obtained on 30 November 2021 (STUDY21080150), from the University of California San Diegos Human Research Protection Program IRB on 14 July 2022 (802047), and from the Boston Childrens Hospital IRB on 25 October 2022 (P00040987). Full study results are planned to be published within 2 years of initial study recruitment (October 2024). Dissemination of findings will occur in peer-reviewed journals, professional conferences and through reports to participating entities and stakeholders. TRIAL REGISTRATION NUMBER: NCT05159713; ClinicalTrials.gov.