The present study targets students' perceptions of study strategies before and during the COVID-19 pandemic's transition to full distance education at a small Swedish university, with the purpose to study how students perceive and form their study strategies. Our inquiries targeted study strategies including various learning strategies such as surface-learning, deep-learning and long-term goal-oriented strategies. Theories of study strategies and self-regulated learning guided our analyses of 15 in-depth interviews with students from different programs, including students with varied experiences of academia. To analyze the dimensions of the phenomenon study strategies, phenomenography was used to explore students' perceptions of their study strategies and conceptualizations of themselves as learners. Students' perceptions of study strategies fell into different categories including also self-perception and goal orientation. We conclude that the pandemic amplified differences between students with deep-learning strategies and satisfactory results and students without distinct study strategies, mainly surface-learning strategies. Students who already before the pandemic applied self-regulated learning, developed their study strategies further during the pandemic experiencing more control, whereas struggling students experienced increased helplessness during full distance education. We call for teachers' increased attention to study strategies in planning and conducting courses, to equalize conditions for groups of diverse students.