This study examines the impact of the COVID-19 pandemic on corporate environmental disclosure practices among manufacturing companies listed on the Indonesia Stock Exchange. Using a sample of 85 firms across the periods before (2018–2019) and after (2020–2021) the pandemic, environmental disclosures were assessed using the Global Reporting Initiative (GRI) standard indicators. Paired sample t-tests and multiple regression analysis were employed to evaluate changes in disclosure levels and to identify key influencing factors. The results reveal a significant increase in environmental disclosure following the onset of the pandemic. Firm size was found to have a positive effect on disclosure, while return on assets (ROA) showed a negative relationship—particularly within the miscellaneous industry group. These findings suggest that larger firms experienced greater external pressure to enhance transparency, whereas profitability alone did not necessarily lead to improved environmental reporting. The study provides valuable insights for regulators and policymakers, emphasizing the importance of targeted disclosure regulations during global crises. In particular, it offers practical input to the Ministry of Environment and the stock exchange authority, indicating that large companies are more inclined to maintain environmental responsibility, even in times of uncertainty.