Purpose: Support services provision and clinical trial enrollment were examined for a cohort of adolescent and young adults (AYAs) diagnosed with having cancer and treated at adult hospitals in Western Australia (WA). Methods: The sample was 383 AYAs aged 15-24 years diagnosed from 2000 to 2004, with follow-up until 2007. Sociodemographic, clinical trial participation, and health service data were obtained from Statewide administrative health data collections and patient medical records at hospitals in WA. Separate multivariate logistic regression models were used to identify which sociodemographic and treatment setting variables predicted whether a patient had formal contact with a mental health professional, social worker, or occupational therapist. Due to the small number of clinical trial enrollments in the sample (n = 5), modeling was not used to explore group differences in this outcome. Results: Mental health professional, social worker, and occupational therapist consultations were received only by patients who attended a metropolitan hospital. Compared with patients treated at only tertiary centers, those treated at only nontertiary centers had lower odds of consulting with a mental health professional (OR = 0.12, 95% CI 0.03, 0.58) or occupational therapist (OR = 0.02, 95% CI 0.001, 0.23). Less than 2% of the cohort enrolled in a clinical trial. Conclusion: Access to clinical trials and support services by AYAs diagnosed with having cancer in WA was generally low, particularly outside the metropolitan area. Variations in accessibility across different treatment settings in WA warrant efforts for greater awareness of AYA needs and increased communication and collaboration between specialists and centers involved in the care of AYAs with cancer.