In-person academic activities post-COVID-19 pandemic have different characteristics than those experienced pre-pandemic. Thus, understanding the cognitive aspects of this activity for students in these various scenarios and focusing on the mental workload becomes a strategy for improving teaching conditions. This study aimed to analyze the mental workload of engineering students at a public institution in southern Brazil during remote teaching (2021) and after returning to face-to-face activities (2023) using NASA-TLX and focus groups, which are related to cognitive performance. For this, a remote questionnaire was sent to all students enrolled at the institution in both periods. The main results indicate increased students’ mental workload, from 73,40 (2021) to 75,18 (2023). Furthermore, the factors that most influenced mental workload during remote teaching were mental demand (83,30) and, during in-person teaching, effort (71,40). These findings reinforce the need to pay attention to constant changes and their consequences in the teaching-learning process, aiming for strategies compatible with the dynamic context currently experienced.