This study aimed to reveal differences in exposure to coronavirus disease (COVID-19) during the first (W1) and the second (W2) waves of the pandemic in six countries among university students and to show the prevalence and associations between exposure to COVID-19 and coronavirus-related post-traumatic stress syndrome (PTSD) risk during W2. The repeated crosssectional study was conducted among university students from Germany, Poland, Russia, Slovenia, Turkey, and Ukraine (W1: n = 1684; W2: n = 1741). Eight items measured exposure to COVID-19 (regarding COVID-19 symptoms, testing, hospitalizing quarantine, infected relatives, death of relatives, job loss, and worsening economic status due to the COVID-19 pandemic). Coronavirus-related PTSD risk was evaluated by PCL-S. The exposure to COVID-19 symptoms was higher during W2 than W1 among students from all countries, except Germany, where, in contrast, the increase in testing was the strongest. Students from Poland, Turkey, and the total sample were more frequently hospitalized for COVID-19 in W2. In these countries, and Ukraine, students were more often in quarantine. In all countries, participants were more exposed to infected friends/relatives and the loss of a family member due to COVID-19 in W2 than W1. The increase in job loss due to COVID-19 was only noted in Ukraine. Economic status during W2 only worsened in Poland and improved in Russia. This was due to the significant wave of restrictions in Russia and more stringent restrictions in Poland. The prevalence of coronavirus-related PTSD risk at three cutoff scores (25, 44, and 50) was 78.20%, 32.70%, and 23.10%, respectively. The prediction models for different severity of PTSD risk differed. Female gender, a prior diagnosis of depression, a loss of friends/relatives, job loss, and worsening economic status due to the COVID-19 were positively associated with high and very high coronavirus-related PTSD risk, while female gender, a prior PTSD diagnosis, experiencing COVID-19 symptoms, testing for COVID-19, having infected friends/relatives and worsening economic status were associated with moderate risk.