Youth-onset type 2 diabetes (T2D) is increasingly common and is often diagnosed shortly before transition from pediatric to adult care. Little is known about the experience of emerging adults (EAs) with T2D and the readiness, barriers, and facilitators to transition. This study sought to describe the illness experience of EAs with T2D and perceptions about transition, and explore themes by “transition readiness,” measured by the Transition Readiness Assessment Questionnaire (TRAQ). In this mixed-methods study, we conducted semi-structured interviews with EAs with T2D using a guide grounded in the health belief model, administered the TRAQ, and collected disease metrics from the electronic medical record. We developed a coding scheme using a directed content-analysis approach and triangulated qualitative and quantitative data to compare themes stratified by mean TRAQ score. Participants described modifying factors like adjusting to life with a chronic illness and coping with mental health issues as critical elements of the illness experience that influence transition. Individual beliefs emerged including the perceived risk of disease complications being informed by experience of family members, self-efficacy in diabetes care hinging on the ability to be highly organized, and transition as a daunting obstacle with numerous emotional and logistical barriers. Participants emphasized the need for support from caregivers and providers throughout transition. Themes did not vary significantly by TRAQ score. Experiences of EAs with T2D suggest more assistance is needed in the transition period to address factors such as mental health, organizational skills, and identifying support people to facilitate care.