Using green financing for PPP funding is an interesting topic among stakeholders in Indonesia. As part of Islamic finance, cash waqf has the potential for sourcing PPP funding, as Indonesia’s potential cash waqf is estimated to reach IDR 180 trillion/year. Grand climate finance and blended finance are participants in nature, so the government-public can participate with cash waqf sources and enter into commercial sectors. The study aims to investigate how actually cash waqf has been implemented in funding public infrastructure. A semi-structured interview was conducted. NVivo was used and was supported by qualitative data storage, coding, and modeling. Then the interviews were categorized into 7 nodes and 38 child nodes. Result of the study reveals that cash waqfs were implemented in some public infrastructures through a blended finance scheme. Some barriers are the most critical issues for successfully implementing cash waqf for public infrastructure funding.