This study is a comprehensive analysis of the environmental, social, and governance (ESG) disclosure levels and board diversity metrics of stock-listed companies in the Baltic states, comparing between two different time points: 2020 and 2022. The approach of the research involves qualitative content analysis of sustainability reports in order to determine disclosure levels, and statistical methods such as t-tests of differences in means to draw conclusions on the differences in disclosure levels based on diversity parameters. The results of the study demonstrate that ESG disclosure scores have improved over time. The average ESG disclosure score increased from 40% in the 2020 sample to 47% in the 2022 sample, with this improvement largely driven by an increase in the disclosure of corporate governance topics. Furthermore, this study provides evidence that companies with female board members and larger boards tend to achieve higher ESG transparency levels. The results show that companies with female members on their boards have higher ESG disclosure levels, with an average of 54% for companies with female members on their management boards compared to 42% for those without, and an average disclosure level of 52% for companies with gender-diverse supervisory boards compared to 42% for those with all-male supervisory board members. The findings of this study contribute to the academic literature by shedding light on the differences in ESG disclosure levels during a time of heightened corporate sustainability awareness, as well as connecting diversity to corporate sustainability.