The current study assessed the effect of the COVID-19 (coronavirus) pandemic on subjective well-being (SWB) and psychological well-being (PWB) and whether the pandemic moderated the effect of personality on well-being. Measures of Big Five personality, SWB (life satisfaction, positive affect, negative affect) and PWB (positive relations, autonomy, environmental mastery, personal growth, purpose in life, self-acceptance) were obtained from a sample of young adults in Melbourne, Australia (n = 1132; 13 July to 11 August, 2020) during a second wave of viral transmission and lockdown, and an identically recruited Pre-COVID sample (n = 547). Well-being was lower in the COVID sample and differences were largest for positive affect (d = -0.48) and negative affect (d = 0.70). While the effect of personality on well-being was relatively robust, the effect of personality on well-being was slightly reduced and the effect of extraversion on positive affect was particularly attenuated during the pandemic.