Capesize ships are cargo ships originally too large to transit the Suez Canal (i.e., larger than both Panamax and Suezmax vessels). To travel between oceans, such vessels used to have to pass either the Cape of Good Hope or Cape Horn. In effect Capesize reads as "unlimited". When the Suez was deepened, the definition of Suezmax changed. Some ships previously unable to transit the canal and deemed Capesize, changed categories.

Capesize vessels are typically above 150,000 long tons deadweight (DWT), and ships in this class include oil tankers in the Very Large Crude Carrier (VLCC) and Ultra Large Crude Carrier (ULCC) classes; supertankers and bulk carriers transporting coal, ore, and other commodity raw materials. The term "Capesize" is most commonly used to describe bulk carriers rather than tankers. A standard Capesize bulker is around 175,000 DWT, although larger ships (normally dedicated to ore transportation) have been built, up to 400,000 DWT. The large dimensions and deep drafts of such vessels mean that only the largest deep water terminals can accommodate them.