Abstract
<jats:p>STEAM approaches create new opportunities for students to develop a wide range of thinking skills connected to technical and scientific education. By combining different areas of knowledge, STEAM encourages students to explore ideas from multiple perspectives and find creative solutions to challenges. This approach is highly relevant in teacher training, as it prepares educators to create innovative and engaging learning experiences. This study examines how an accredited teacher professional development workshop supported in-service secondary teachers in designing mobile game-based learning experiences for sustainability through the integration of STEAM, Universal Design for Learning, and Open Schooling. The study adopted a qualitative case study design based on thematic analysis of documents related to games created by teachers, implementation presentations, and teachers’ reflections. The analysis shows that the workshop supported teachers in moving from a user-oriented relationship with educational technology towards a design-oriented and authorial role. UDL was the most prominent workshop theme, reflected in multimodal and motivational features, as well as teachers’ perceptions of positive student engagement. Technological reliability, accessibility, and data-validity issues remained important constraints. This context supported professional development by enhancing teachers&#039; capacity to design STEAM, inclusive, and place-based digital learning experiences for sustainability, while articulating the OpenUS4ALL and EduCITY projects.</jats:p>