The Mon Calamari Exodus Fleet represented a fleet of Mon Calamari ships that managed to flee the Galactic Empire's subjugation of their homeworld, the aquatic Mon Cala. City-ships, which the Empire initially mistook for mere buildings, rose from the oceans and escaped Mon Cala. This fleet was composed of numerous vessels, including MC75 Star Cruisers, and was under the command of Admiral Raddus aboard the Profundity. It would later integrate into the fleet of the Alliance to Restore the Republic, becoming an essential part of it.
The Galactic Empire initiated an invasion of Mon Cala in 18 BBY after a Jedi infiltrator assassinated the ambassador stationed there. Lee-Char, the king, instructed Raddus, the mayor of Nystullum, to take responsibility for the defense of the planet's southern hemisphere, while Gial Ackbar, his Chief of Security, was tasked with protecting the northern region.
While Ackbar wreaked havoc on the forces of Colonel Bergon, Raddus developed a unique and innovative tactic. He gathered five MC80A Home One Type Heavy Star Cruisers along with several smaller ships from the Mon Cala Mercantile Fleet and linked their shields together, creating a large protective barrier that could withstand any assault. Moff Wilhuff Tarkin admired the strategy, remarking that Raddus had essentially built himself a fortress. Raddus's small fleet effectively defended the southern hemisphere of Mon Cala with relative ease. However, in the north, Tarkin began a bombardment of the planet from his Imperial-class Star Destroyer, the Sovereign. The Sovereign, along with its two escorting Star Destroyers, destroyed numerous settlements and caused billions of casualties. Despite being informed of this, Raddus instructed his forces to maintain their position, continuing to hold the Imperial forces at bay in the south.
Later, Lee-Char issued a broadcast ordering all of his forces to cease fire. Raddus was shocked by this decision and refused to comply. To make matters worse, Tarkin began targeting locations in the southern hemisphere, bringing the attacks dangerously close to Raddus's ships. Without the ability to deflect the turbolaser fire, the small fleet's time was limited. Consequently, Raddus ordered the ships to unlink their shields and attempt to break through the blockade. The five cruisers separated and headed towards the Star Destroyers. As they passed the Sovereign, two of the cruisers were destroyed. However, Raddus successfully navigated through with the remaining three cruisers. Tarkin instructed his gunners to power down, confident that they would eventually be found.
Following the battles on Mon Cala, the Empire initiated the subjugation of the planet, which triggered a mass departure. Raddus led the effort, with three MC80As surviving the initial escape attempt from the occupation. He ultimately gained ownership and command of the Profundity, leading the first major emigration from the planet. The initial wave included MC75 Star Cruisers, such as the Aspiration, which had been converted from city buildings on Mon Cala. Years later, as part of the emerging Rebel Alliance, several Mon Cala city-ships were transformed into the Telaris rebel stardocks, situated in the Telaris cometary cloud. At these stardocks, Mon Calamari cruisers were refitted, with the Profundity being the first to complete the process, followed by the MC80A Home One Type Heavy Star Cruisers Home One and Nautilian. The Nautilian would have finished refitting before the Home One if it hadn't been for the Ishanna inversion.
During Mon Cala's occupation, the Exodus Fleet consisted of at least five star cruisers along with several smaller vessels. Following the occupation, the fleet expanded to include more ships, encompassing various Star Cruisers and city-ships. As the initial wave of the mass departure from Mon Cala, the fleet acquired MC75 cruisers like the Profundity and Aspiration, as well as MC75 Armored Cruisers and MC75 Ordnance Cruisers. The fleet also included a minimum of two Sphyrna-class Hammerhead corvettes.