The Teaching Science as Inquiry (TSI): Aquatic professional development (PD) project was conducted by researchers and curriculum developers at the Curriculum Research & Development Group (CRDG), College of Education, University of Hawai‘I at Mānoa from 2011–2014. The project, Accessible Professional Development for Teaching Aquatic Science Inquiry, was funded through a U.S. Department of Education Institute for Educational Sciences (IES) grant (No. R305A100091). The project was an inquiry-based, year-long, modularized professional development (PD) for middle and high school teachers focused on aquatic science. The evaluation of the project was an eclectic, mixed-method study, which used instruments for collecting both formative-evaluation and summative-evaluation information.