The WHO World Mental Health International College Student (WMH-ICS) Initiative aims to assess the prevalence of mental disorders among college students worldwide and implement Internet-based interventions to prevent and treat mental disorders. The symposium comprises three presentations by researchers from Sweden and Hong Kong who are part of the worldwide consortium. The first presentation shares the epidemiological findings from 17,948 students at 15 higher education institutions in Sweden. Prevalence for any 30-day, 12-month, and lifetime diagnosis of any mental disorder is 25.2%, 39.3%, and 44.5%, respectively. The very high prevalence calls for readily accessible and highly scalable interventions that can reach a large population of emerging adults. Preliminary findings from a randomized controlled trial comparing guided or unguided Internet-based cognitive behavioral therapy will be presented. The second presentation shares findings from a longitudinal study of 2796 students from higher education institutions in Sweden investigating changes in mental health and academic self-efficacy during the course of the COVID-19 pandemic when college teaching was abruptly changed to online remote mode. Findings showed that worsening of mental health is associated with dampening of academic self-efficacy longitudinally. Implications for timely online support for students to adjust to uncertainties is necessary to promote students’ mental health and academic success. The third presentation shares a series of studies conducted in Hong Kong that systematically examine college students’ preferences and experiences in using online interventions and self-care exercises. Specifically, mixed methods in the format of qualitative interviews and user surveys were used to examine users’ perceived needs and preferences, usability, and acceptability in using digital mental health tools to manage their mental health and build self-care habits. Facilitators and barriers were identified. Then, preliminary findings from a 4-arm randomized controlled trial comparing the relative effectiveness of coach-guided or self-guided transdiagnostic cognitive behavioral therapy, self-guided mindfulness-based intervention with waitlist control in managing depressive and anxiety symptoms will be shared. Insights regarding to prevalence of college students’ mental health challenges, usability and effectiveness of Internet-based interventions, and challenges in uptake and engagement of online interventions among emerging adults will be discussed. The experience of integrating offline counseling services with digital mental health platforms across higher education institutions in Hong Kong will also be shared.