Ship energy efficiency has become a subject of intense attention and development due to the growing awareness of the maritime industry's impact on the environment. Shipping is responsible for a significant share of global greenhouse gas emissions, which directly contributes to climate change and global warming. Given that maritime transport plays a crucial role in global trade, improving the energy efficiency of ships is considered vital to reducing this impact. This paper presents the instruments introduced by the International Maritime Organization with the aim of reducing pollution and increasing the efficiency of ship installations. The paper describes the Energy Efficiency Design Index (EEDI) and the Energy Efficiency Existing Ship Index (EEXI). It also considers the Ship Energy Efficiency Management Plan (SEEMP), the Energy Efficiency Operational Indicator (EEOI), and the Carbon Intensity Indicator (CII). These measures are crucial in the effort to improve energy efficiency and reduce the ecological footprint of the maritime sector.