This study aims to explore the challenges and strategies in creating online communities for individuals with diabetes, emphasizing their role in fostering connections among individuals facing similar health conditions. Using a single-case approach, we investigated the design process of a diabetes online community using the classic waterfall model. Participants were recruited from a diabetes local association, and usability was assessed using the System Usability Scale and the think-aloud method. Subsequently, semistructured interviews were conducted to evaluate functionality and user experience. Data collection was conducted from August until December 2023. The development of the community unveiled significant usability challenges, highlighting the need for user feedback and improvement. Ethical considerations, including anonymity, usage conditions, privacy terms, and health information sharing, emerged as critical areas requiring meticulous attention. Furthermore, healthcare professional moderation was deemed essential to ensure a secure environment. Users expressed strong interest in enhanced interaction features and personalized notifications. Although online diabetes communities hold potential for peer support, addressing usability challenges, ethical considerations, and moderation issues is essential. This study emphasizes the ongoing necessity for research to enhance the development of patient communities, ensuring accessibility, mitigating ethical risks, and leveraging nurses as moderators.