The use of long-acting reversible contraceptives (LARCs) has been increasing across the US and among young people, specifically. With recent political pressures around reproductive health, the potential for prioritizing high-efficacy methods or coercion in healthcare visits may supersede the needs of patients, especially when they’re young. To support reproductive autonomy, we propose a policy-relevant research study to center the needs of young, marginalized LARC users during a period where their needs and preferences shift during emerging adulthood. Utilizing existing data from a large cluster randomized trial among community colleges in California and Texas, we propose an explanatory mixed methods analysis among a diverse group of young people to assess changes in LARC use, preferences, and needs during emerging adulthood. First, we will assess longitudinal contraceptive agency patterns among LARC users and determinants of such patterns over time. From this cohort, we will recruit participants for in-depth interviews to elucidate LARC user experiences, needs, and preferences, allowing young people to tell their stories, including both positive and negative aspects of their experiences. Throughout this process, we will engage both a Community Advisory Board and a Youth Advisory Board to co-create research questions, to provide ongoing feedback on our interpretations, and to center their perspectives in dissemination of the findings. With these data, we will generate high-quality evidence from a large study across these contexts to inform both clinical practice and potential policy advances for young people living in abortion ban and protective states.