ULCC or Ultra Large Crude Carrier - "Supertankers" are the largest shipping vessels in the world, and the largest man-made mobile structures with a size ranging between 320,000 to 500,000 DWT. These ships can transport 2,000,000 barrels (320,000 m3) of oil/318,000 metric tons. Due to their mammoth size, they need custom built terminals. As a result they serve a limited number of ports with adequate facilities to accommodate them.

They are primarily used for very long distance crude oil transportation from the Persian Gulf to Europe, Asia and North America. ULCC are the largest shipping vessels being built in the world with standard dimensions of 415 meters length, 63 meters width and 35 meters draught.