The COVID-19 pandemic has considerably impacted many people's lives. This study examined changes in subjective wellbeing between December 2019 and May 2020 and how stress appraisals and coping strategies relate to individual differences and changes in subjective wellbeing during the early stages of the pandemic. Data were collected at 4 time points from 979 individuals in Germany. Results showed that, on average, life satisfaction, positive affect, and negative affect did not change significantly between December 2019 and March 2020 but decreased between March and May 2020. Across the latter timespan, individual differences in life satisfaction were positively related to controllability appraisals, active coping, and positive reframing, and negatively related to threat and centrality appraisals and planning. Positive affect was positively related to challenge and controllable-by-self appraisals, active coping, using emotional support, and religion, and negatively related to threat appraisal and humor. Negative affect was positively related to threat and centrality appraisals, denial, substance use, and self-blame, and negatively related to controllability appraisals and emotional support. Contrary to expectations, the effects of stress appraisals and coping strategies on changes in subjective wellbeing were small and mostly nonsignificant. These findings imply that the COVID-19 pandemic represents not only a major medical and economic crisis, but also has a psychological dimension, as it can be associated with declines in key facets of people's subjective wellbeing. Psychological practitioners should address potential declines in subjective wellbeing with their clients and attempt to enhance clients' general capability to use functional stress appraisals and effective coping strategies. (PsycInfo Database Record (c) 2021 APA, all rights reserved).