Does COVID-19 change the willingness to cooperate? Four Austrian university courses in economics play a public goods game in consecutive semesters on the e-learning platform Moodle: two of them in the year before the crisis, one immediately after the beginning of the first lockdown in March 2020 and the last one in the days before the announcement of the second lockdown in October 2020. Between 67% and 76% of the students choose to cooperate, i.e. contribute to the public good, in the pre-crisis year. Immediately after the imposition of the lockdown, 71% choose to cooperate. Seven months into the crisis, however, cooperation drops to 43%. Depending on whether two types of biases resulting from the experimental design are eliminated or not, probit and logit regressions show that this drop is statistically significant at the 0.05 or the 0.1 significance level.