This research was informed by a constructivist approach to learning, with a focus on answering the research question: what skills can science teachers promote and encourage among students through designing and implementing problem-based learning in their classrooms? The research was carried out in a co-education secondary school in England and involved fifty-two Key Stage 3 students (second year of secondary education), aged 13 years old. It utilized a theoretical framework of the 3C3R model (3C- content, context, and connection, and 3R- researching, reasoning, and reflecting) in problem-based learning (PBL). Data were collected through lesson observations, interviews, and focus groups. It was analyzed using thematic analysis and the recurrent themes were coded by creating relationships and links to the problem-solving skills promoted by PBL. The study found that the application of prior knowledge, collaborative learning, modeling and eliciting feedback were the skills promoted by PBL and these are valuable in problem-solving. However, collaborative learning was the dominant skill promoted by PBL. Teachers' pedagogical knowledge and the time students spent researching were limiting factors in promoting problem-based learning, thereby suggesting the need for continuing professional development for teachers and further integration of blended PBL to maximize learning time.