A large cruise ship ranging in length from 900 to 1,100 feet might hold 1 to 2 million gallons of fuel. Smaller vessels, like a 440-foot-long ferry, might carry around 130,000 gallons of fuel, while a gigantic ship measuring over 1,300 feet in length can tote over 4 million gallons.

Ship fuel tanks in 2026 are sized based on the vessel's role and route, often reaching staggering capacities. A large Ultra Large Container Vessel (ULCV) or a modern cruise ship like the Icon of the Seas typically has fuel storage capacity between 8,000 and 12,000 cubic meters (roughly 2 to 3 million gallons). To put this in perspective, filling a single tank could cost several million dollars at 2026 bunker fuel prices. These tanks are actually a series of "cells" distributed throughout the hull for stability and safety. In 2026, there is a major shift toward LNG (Liquefied Natural Gas) tanks, which require specialized vacuum-insulated, double-walled structures that take up more space than traditional heavy fuel oil tanks. These LNG tanks are often "Type C" pressurized tanks, designed to keep the gas at -162°C. A single trans-Pacific voyage for a cargo ship might consume over 2,000 tons of fuel, necessitating these massive, multi-million-gallon storage systems.