This study mapped self-reported sexual acts among students during the COVID-19 pandemic, as well as how they changed compared to the year preceding the pandemic, within the context of Flanders, Belgium. Given the growing literature that has identified students as a risk group for mental health problems, particularly during the COVID-19 pandemic, and the importance of sexual development during emerging adulthood, the current study additionally examined whether these (changes in) sexual acts were related to students' mental health. A representative sample of higher education students from a major Belgian university was used (N = 1580, 41.60% male and 58.40% female). This study showed fewer students engaged in sexual acts with physical contact and more in sexual acts without physical contact, which was shown to be associated with higher and lower sexual satisfaction, respectively. In addition, changes in sexual acts were associated with sexual satisfaction: Students who engaged in sexual acts with physical contact prior to the pandemic, but did not engage in sexual acts during the pandemic, were more likely to experience reduced sexual satisfaction. Students who did not engage in sexual acts before the pandemic, but did engage in sexual acts without physical contact during that time, were more likely to be sexually satisfied. Sexual satisfaction, in turn, indirectly affected depressive feelings. These results contribute to the understanding of how students' mental health was affected during the COVID-19 pandemic by examining their sexual activity. The results of the study should, however, be interpreted in light of several limitations, such as the use of self-reported and cross-sectional data.