Data donation is a potential means of feeding more data into data-driven projects. However, little is known about how it differs from existing data collection methods used by designers and what influences individuals’ act of donating data to design projects. By conducting expert interviews with a prototype of the Data Donation System and user tests with an interactive prototype of the Data Donation App, I’ve proposed a system of donating data to design projects in an ethical manner. The findings mainly contribute to adding new knowledge of applying data donation in domains outside of healthcare research and guiding designers and their team to motivate users to donate their data to design projects.