This study examined how the rapid spread of telework triggered by the COVID-19 pandemic has affected organizational behavior, especially teamwork. The spread of COVID-19 in 2020 led to a significant increase in telework in Japanese companies. Since telework involves non-face-to-face communication, it may have a negative impact on teamwork. We compared the teamwork of 23 teams in an organization by conducting a pre- (January 2020) and post-survey (May 2020) during the first wave of COVID-19 in Japan. We found that the proportions of telework and team virtuality increased significantly from pre-survey to post-survey. However, the teamwork and team performance data remained almost constant. Rather, on examining the data from May 2020 (post-survey), we found that team virtuality, especially technology use, had a positive correlation with teamwork. Thus, the rapid spread of telework and team virtuality does not necessarily hamper teamwork; rather, the technology-proficient teams may have excellent team processes and high team performance.