Indonesia's curriculum transformed the focus from rote memorization to engaging students in solving real-world problems and thinking critically, as emphasized in the problem-based learning (PBL) approach. The success of PBL heavily depends on the competence of teachers in designing effective lesson plans that can stimulate this deeper level of student engagement, which is still limited in secondary EFL practices. This case study explores teachers’ perspectives and planning competence in developing the PBL approach under the established curriculum. Four in-service English teachers with over two decades of teaching experience are recruited as the participants. The collected data is analyzed thematically under the framework of social constructivism and the humanistic approach. The findings demonstrated teachers’ proficiency in designing lesson plans that meet the standardized curriculum components and the PBL theoretical framework. Their efforts are reinforced by their collaborative planning and reflective teaching practices. However, the designed PBL lesson plans dealt with several challenges, including diverse student competencies, unique characteristics, classroom management issues, utilization of digital technology, and administrative burdens. Recognizing these challenges emphasizes the need for educational reforms and support systems that empower teachers to create a conducive and effective PBL learning environment for their students. Addressing these issues requires systemic support, professional development opportunities, and a shift in policy focus from compliance to effective pedagogical practice.