Metacognition is a core process in human learning. The problem is that learners are not often aware of their metacognition. The purpose of this study is to examine learners' metacognitive awareness in terms of their situation-specific perceptions in collaborative learning tasks. Upper elementary school students (N = 92) filled in a Metacognitive Awareness Inventory (MAI) and situated self-reports that assessed their individual metacognitive interpretations about task difficulty and task understanding. Also, the students' actualised knowledge about the topics was assessed via knowledge tests. The results showed that students who have high metacognitive awareness know what they are supposed to do in this task and find the task easier, especially when they are exposed to more collaboration. Importantly, the way students perceive a task after the learning situation predicts their learning outcomes. The findings of this study can help with designing awareness tools for collaborative learning tasks.