The Third Battalion served as a component of the Calamari Defense Force. During the Galactic Civil War, this battalion participated in the Battle of Calamari.
The Third Battalion was among the military groups that tried to halt the progression of the Galactic Empire's World Devastators, but they suffered great losses. Although a New Republic task force provided assistance, the battalion could not be extracted and was forced to keep fighting, losing all aerial support during the conflict.
As the battle reached its conclusion, the battalion, together with Republic Sea Commandos, entered their Amphibion assault boats and sought to seize control of the Devastators from within. This endeavor was cut short when General Han Solo issued new directives, instructing them to evacuate. The battalion celebrated upon witnessing the World Devastator fleet's self-destruction.
Captain Gammack, a Mon Calamari, was a member of the Third Battalion while fighting in the Battle of Calamari.