3D printing technology is a powerful educational tool that can promote integrative STEM education by connecting engineering, technology, and applications of science concepts. Yet, research on the integration of 3D printing technology in formal educational contexts is extremely limited. This study engaged preservice elementary teachers (N = 42) in a "3D Printing Science Project" that modeled a science experiment in the elementary classroom on why things float or sink using 3D printed boats. The goal was to explore how collaborative 3D printing inquiry-based learning experiences affected preservice teachers' science teaching self-efficacy beliefs, anxiety toward teaching science, interest in science, perceived competence in K-3 technology and engineering science standards, and science content knowledge. The 3D printing project intervention significantly decreased participants' science teaching anxiety and improved their science teaching efficacy, science interest, and perceived competence in K-3 technological and engineering design science standards. Moreover, an analysis of students' project reflections and boat designs provided an insight into their collaborative 3D modeling design experiences. The study makes a contribution to the scarce body of knowledge on how teacher preparation programs can utilize 3D printing technology as a means of preparing prospective teachers to implement the recently adopted engineering and technology standards in K-12 science education.