Integrated Science and Social Studies (IPAS) learning in primary schools requires active student engagement, critical thinking, collaboration, and contextual problem-solving. However, classroom implementation continues to face challenges, including limited identification of students’ learning needs, insufficient collaborative and problem-solving activities, and inadequate feedback and reflection. This study aimed to analyze problems in IPAS learning activities based on classroom observations of teacher activities, student activities, classroom interactions, and the learning environment. The analysis was informed by Design Thinking, active learning, student-centered learning, formative assessment, and collaborative learning perspectives. A non-participant observation method was employed using a structured binary-scale (“Yes”/“No”) instrument comprising 38 indicators across the three observation domains. The findings revealed relatively limited implementation in teacher and student activities, while classroom interaction and the learning environment demonstrated comparatively stronger performance. Positive practices included clearly communicated learning objectives and teachers’ openness to students’ opinions. However, weaknesses remained in collaborative learning, the use of instructional media, problem-solving activities, feedback, and end-of-lesson reflection. From a Design Thinking perspective, the learning process partially reflected the Empathize and Define stages, whereas the Ideate, Prototype, and Test stages were not yet systematically implemented. These findings highlight the need to strengthen the identification of students’ learning needs, redesign collaborative and problem-solving activities, optimize instructional media, and ensure continuous feedback and reflection. Such improvements may support more student-centered, interactive, and meaningful IPAS learning in primary schools.