Empowering teachers as instructional designers strengthen the link between theory and good practice. The purpose of the research is to explore two teachers' experiences about a professional development (PD) program. The PD includes a one academic year program with the aim of developing teachers' instructional design knowledge and skills using Understanding by Design model as reference. Teachers' instructional designs improved in terms of UbD design principles, and they reported change in their attitudes and teaching practices after the fourth cycle. Continuous discipline-specific feedback and trust bond based on prolonged communication underlined as major elements of PD that facilitated teacher change.