Contribution: This study represents the first systematic attempt to develop Science, Technology, Engineering, Arts, and Mathematics (STEAM) integrated project-based learning (PBL) as a transdisciplinary teaching method for fostering students' creativity and computational thinking (CT) skills. Background: With the growing importance of creativity and CT skills in the modern world, there is a need for innovative teaching methods that can effectively nurture these abilities in students. This study explores the potential of integrating STEAM into PBL as a transdisciplinary teaching approach to address this need. Intended Outcomes: The outcomes of this approach include significant improvements in various dimensions of students' creativity (fluency, flexibility, originality, and elaboration) and enhanced CT skills, particularly in medium and hard tasks. Application Design: The study involved 54 junior high school seventh-graders, with 28 students in the experimental group and 26 students in the comparison group. The experimental group was exposed to a semester of STEAM PBL, while the comparison group followed the regular curriculum. Findings: After a semester of STEAM PBL, the experimental group demonstrated significant improvements in creativity dimensions, while the comparison group showed no significant changes. In terms of CT skills, the experimental group exhibited significant improvements in medium and hard tasks, whereas the comparison group did not. These results highlight the potential benefits of integrating STEAM into PBL as a transdisciplinary teaching approach for enhancing students' creativity and CT skills. The implications for educational practice and future research are discussed in depth.