Created by the Earth Alliance as its main type of battleship, Nelson-class ships were built in massive numbers. Like the Drake-class, ships of this class are part of every space fleet which the Alliance controls. Sometimes, Nelson-class vessels even serve as flagships of smaller fleets. One such example was the Montgomery, which was the flagship of the advanced force of the 8th Fleet, and was destroyed during the Battle near Junius Seven. Several Nelson-class vessels were also part of this fleet, including the Cassandros, Paris, and Ptolemaois. These ships however were easily defeated by the four stolen Gundams now used by ZAFT during the Battle of Orbit.
After the First Alliance-PLANT War, the Nelson-class was upgraded with the addition of two linear catapults, making them effective mobile suit carriers. The ship class now carried the more advanced GAT-02L2 Dagger L and GAT-04 Windam mobile suits. Near the end of the Second Alliance-PLANT War, a number of these ships and their crew defected to the Terminal fleet led by the ships of the original Three Ships Alliance and fought to end the war.