Aims: This study aims to compare the incident rate of sports injuries before and during the COVID-19 quarantine among active and nonactive adults and identify and compare patterns, types and sites of sports injuries. Study Design: Cross-sectional study. Place and Duration of Study: A self-administered online survey was conducted in Riyadh, Saudi Arabia, between June 2020 to November 2020. Methodology: We conducted a descriptive, cross-sectional web-based survey on active and nonactive adults of Riyadh, Saudi Arabia. A total of 537 respondents from Riyadh completed the questionnaire. The study included adults active during quarantine who are also residents of Riyadh. Residents of other cities and respondents younger than age 18 or older than 64 were excluded. Results: A total of 537 participants fulfilled the criteria. More than half of the respondents were aged 18 to 24 years (54.7%). Of those who did not exercise before quarantine, 42.9% (n = 91) started during quarantine, while 26.5% (n = 86) of respondents who exercised before quarantine stopped during the quarantine. Running and walking were the most common sports practiced by 70.9% of respondents during quarantine and 63.1% before the quarantine. Muscle strain/tears were the most common injuries before quarantine (26.2%), while bruises were the most common injury during quarantine (28.6%). Soccer and basketball were the most affected by quarantine. Conclusion: The number of active individuals had increased during quarantine. Paradoxically, the prevalence of sports injuries decreased. Soccer and basketball were the most significantly affected by a lack of participation during the quarantine; both were a common cause of sports injuries. Medical providers should investigate and support preventive measurements on sports that cause most injuries.