In line with the global trend for environmental protection, the shipping industry is also making significant efforts. The International Maritime Organization introduced carbon intensity indicator and energy efficiency existing ship index to reduce greenhouse gases and presented “Initial IMO Strategy on reduction of GHG emissions from ships”. In contrast to previous environmental indices, carbon intensity indicator is calculated based on the operation information of ship. In this study, the annual fuel consumption was calculated based on the operation information of 4,151 ships and CO2, N2O, and CH4 emissions among greenhouse gases were estimated. The results of the study showed that CO2 accounted for 98% of the greenhouse gases emitted from ships, the highest, and N2O and CH4 were found to be insignificant at 1.5% and 0.5%. The major types of ships that emitted greenhouse gases were cargo ships, chemical tankers, oil tankers, and gas carriers. Ships subject to data collection system and carbon intensity indicator regulations include only 69% of the fuel consumed by all ships. This proportion increases to 87% of the total fuel consumption if it is expanded to include ships over 400 GT that are regulated by energy efficiency existing ship index.