A contact-tracing application is implemented to monitor and manage the spread of disease during pandemics. Since its launch by the government, the adoption of the PeduliLindungi, an Indonesian contact-tracing application, has remained low. PeduliLindungi users are only 34 % of smartphone users and 20% of the population in Indonesia. The effectiveness of contact-tracing apps cannot be measured without mass use and adherence to protective behavior. Approximately 80% of smartphone users, or 56% of the overall population, must use the app. Therefore, the app implementation challenges need to be researched to develop strategies to increase user adoption. This study used a qualitative methodology by conducting interviews with 17 respondents. Respondents were recruited using the purposive sampling method. This study used the NVIVO application to process and analyze data. Based on the results of data analysis using thematic coding, the challenges in contact-tracing apps implementation in Indonesia are divided into five main themes: technology limitations, lack of socialization, organizational problems, individual concerns, and socio-economic inequalities. This study contributes to the theory of challenges in contact tracing app implementation. The technical contributions and recommendations are also provided.