The Antietam class is very similar in appearance to the Columbus-class supply ship and bears fundamentally the same design, however it features larger, more noticeable engines that extended outward from the main body of the ship to either side. The bridge, though the same shape and in basically the same location, is raised above the level of the rest of the ship. The main fuselage of the ship is longer and the dorsal body of the ship features a few drosaly raised sections not present in the Columbus.
The Antietam-class had no armaments and was completely unprotected if it did not have an escort. It depends upon their mobile suits to protect them and fend off enemy units. It can carry multiple GM units within their hangers and be refueled and resupplied quickly during battles. The Antietam-class appears nearly, if not completely, identical to the Columus Kai-class. It is unclear if they are different or a redesignation of the same class. Twenty-four ships were known to have been constructed.