The purpose of this study was to explore how undergraduate college students formed partnerships in informal educational teams to design and build an interdisciplinary, ill-defined, integrated science, technology, engineering, and mathematics (STEM) project and translate it to lessons taught to a pre-collegiate student (e.g., K-12 in the US) audience. The authors pursued two research questions: (a) How does an authentic research project provide space for integrating STEM disciplines? (b) How does an authentic research project impact partnerships among team members? Nine undergraduate college students were accepted into the 2020 cohort, forming three teams of three undergraduates each. Teams were roughly composed of one engineering major, one science major, and one education major. Methods of data collection included interviews and field notes. Data were analyzed by assessing the level of partnership achieved based on an already established model. Results indicate that all teams progressed through pre-partnership to at least the partnership (little p) level. Two partnership dimensions achieved the highest (big P) level: one of perception of benefit and one of products and activities. The results have implications that integration of STEM disciplines and forming partnerships could be related, and that building teamwork skills results in products of higher quality. The results are linked to previous research and recommendations for more effective partnerships are provided.