Background: STEM is an interdisciplinary holistic approach that combines the fields of technology and engineering in science and mathematics disciplines. STEM contributes to students' academic success, 21st century skills, and perspectives towards science. The scarcity of international studies focusing on the implementation of STEM in primary schools, particularly in the Turkish educational context, raises concerns about the contribution and challenges associated with this approach. The lack of research in this area inhibits a comprehensive understanding of the barriers hindering successful STEM integration in Turkish primary education. Purpose: The purpose of this study is to see how 4th grade students' success, 21st century skills, and perspectives about the lesson are affected by learning about magnetism through STEM activities. Sample: The research group consists of 48 students from two classes in the fourth grade at a primary school in the district centre of a city in the Central Black Sea Region in Türkiye. Design and Method: A quasi-experimental design with a pre-test - post-test control group was used in this study. The Magnetism Achievement Test and the 21st Century Learning and Renewal Skills Scale were used to collect data for the study. Furthermore, clinical interviews were conducted to ascertain the students' perspectives on the course. Results and Conclusion: The study found that student success was higher in the experimental group, where lessons were taught with STEM activities, than in the control group. Therefore, it was found that students learned the subject of magnetism better with STEM-based activities. The experimental group's students' 21st century skills improved as well at the end of the implementation. The experimental group students, who were taught STEM activities, were found to have positive perspectives toward the lesson. In conclusion, integrating STEM activities into teaching practices appears to enhance student learning outcomes and foster the development of 21st century skills. Educators are encouraged to incorporate such activities into their curriculum to promote engagement and deeper understanding of subject matter.