The integration of environmental, social and governance (ESG) principles in the maritime sector has become an essential component in enhancing sustainable development and operational transparency. This article explores the growing importance of ESG frameworks in the maritime industry, focusing on the practical applications and comparative assessment of ESG performance among four major European ports: the Port of Rotterdam, the Port of Antwerp-Bruges, the Port of Klaipėda, and A. P. Moller-Maersk. The paper investigates ESG maturity through a set of defined indicators, such as emissions, renewable energy use, green investment, social performance and governance transparency, offering a critical evaluation of their implementation across different port management

models. The findings highlight significant variability in ESG integration, with Rotterdam and Maersk leading in environmental and governance indicators, while Antwerp-Bruges and Klaipėda are still developing their ESG reporting practices. The study underscores the importance of standardised ESG frameworks, transparent reporting, and digital innovation for advancing sustainability in the maritime sector.