The Indonesian One Data policy is designed to improve internal government data governance practices by providing a regulatory framework concerning organizational structure, including the roles, tasks, and responsibilities of each key stakeholder. It also specifies mechanisms to ensure the preparation, collection, and/or processing of data that meets data standards, the application of metadata according to the standard format, and dissemination of data according to the principles of data interoperability. We conducted a data journey modelling for three key health datasets to identify challenges and barriers in data flow across local and national government agencies. The findings highlight the critical role of the local government leaders and data custodians, enforcement of data standards and policies, and compliance (including a mechanism to enforce penalties for non-compliance) to the successful implementation of the One Data policy in Indonesia.