The COVID-19 pandemic had a significant impact on educational and sporting systems worldwide, with, for example, school closures, transitions to remote teaching, and limited opportunities for practicing sports. Consequently, this study aimed to explore how student-athletes and teachers at certified sports-oriented high schools in Sweden experienced uncertainty in relation to the COVID-19 pandemic and how the pandemic impacted their everyday life experiences and well-being. This study is based on a secondary analysis of two former studies that explored the experiences of teachers and student-athletes at certified sport-oriented upper secondary schools in Sweden during the COVID-19 pandemic. In study one, individual in-depth interviews were conducted with 13 teachers (mean age: 44 years). In study two, 53 student-athletes (mean age: 18 years) participated in focus group interviews. The amplified secondary analysis was based on qualitative content analysis and allowed for posing new research questions to the existing data and examining common and divergent themes across the two datasets. The analysis resulted in four themes: ‘Social life in uncertain times’, ‘Uncertainty affects health and well-being’, ‘Rapid changes, uncertainty, and adaption’, and ‘Lessons learned for the probabilistic future’ that illuminate the student-athletes and teachers experiences. The student-athletes and teacher experiences shared some similarities (e.g., decreased social contacts and loneliness, uncertainty in relation to constantly changing restrictions). Importantly, however, their experiences also differed in several ways; for example, the teachers coped better with the second lockdown, while the second lockdown was more difficult to handle for the student-athletes. In conclusion, the study highlights the multifaceted impact of the COVID-19 pandemic on student-athletes and teachers’ social lives, study and work situations, opportunities for practicing or teaching sports, and well-being. The results emphasize the need for support, flexibility, and preparedness for future uncertainties, such as new pandemics, for student-athletes and teachers.