Solar PV capacity growth in Japan has been facilitated by a number of government schemes that have been implemented since 1994. Publicly available capacity data are provided by a number of agencies and organisations at various resolutions and at different stages within these schemes. This study provides a comprehensive review of solar PV data sources in Japan between 1994 and 2019, as well as an introduction to the subsidy schemes and organisations involved in scheme management and data collection in Japan. As a result, the authors produced their own dataset of installed capacities and generation across time for the various regions. Lastly, this study provides insights and recommendations to policy makers regarding opportunities for improving the accessibility and quality of data from a user perspective and to enhance Japan’s presence in international research.