Background: Since the COVID-19 pandemic emerged, humanity has had to face unprecedented change in daily routines. Therefore, the pandemic has also had an impact on mental health. Most of the literature analyzes adult experiences during the COVID-19 pandemic, while the youth is less investigated. The purpose of this study was to reveal adolescent experiences during COVID-19. Methods: This qualitative study consisted of 19 adolescents from 11–17 years old. Semi-structured in-depth interviews were conducted, and thematic analysis was applied. Results: Five themes were identified: ambivalent feelings; daily routine changes; disappointment with distance education; coping strategies; and discoveries. Conclusion: The study revealed adolescents’ mostly negative feelings such as sadness, anger, loneliness, or boredom. They shared about frustrating daily routine changes and shifting to a distance education mode that was quite limited in effectiveness and convenience. Nonetheless, communication with family, peers, pets, active leisure, and favorite activities helped them to cope with the difficulties during COVID-19. During this period, adolescents had more free time for themselves and personal growth, found new activities, or improved some relationships. Overall, the COVID-19 pandemic had mostly negative side effects, and regardless of positive experiences, it was mainly considered by adolescents as an adversity for their mental health.