The SERENITY project is a 24-month Erasmus+ Cooperation Partnership in Youth (2025–2027) focused on promoting digital well-being and youth mental health through peer education. Coordinated by SYAJ – Synergia Association (Portugal), in partnership with Digital Media Zone (Ireland) and Media Suite Academy (Greece), the project responds to the growing impact of excessive digital use, cyberbullying, social media pressure, and online addiction on young people’s mental health. Serenity aims to empower youth to become peer educators, creating a supportive network where young people can help each other build healthier digital habits and stronger emotional resilience. The project combines digital education, mental health awareness, and youth leadership to increase understanding of how online behaviours affect well-being and to promote safer, more balanced engagement with technology. Through its activities, Serenity will create a Digital Well-being Toolbox with interactive infographics, quizzes, videos, and online modules; develop a Peer Education Training Programme that equips young people with leadership, communication, and conflict resolution skills; and implement a Peer Outreach Programme where trained youth leaders organise workshops, coffee mornings, mental health walks, and informal community sessions to support their peers. The project seeks to train young people as digital well-being ambassadors, strengthen youth participation in community initiatives, and create a sustainable peer-led support system that continues beyond the project’s duration. Ultimately, Serenity positions young people not only as beneficiaries but as active changemakers, helping build healthier digital environments and stronger communities across Europe.