At the start of the conflict, "Almirante Antequera" was in Santander. She sailed to Málaga on 19 July 1936, arriving on 21 July. After a patrol mission, some of her officers who sided with the rebels turned themselves in to the Republican authorities. During the war, she patrolled the area around the Strait of Gibraltar. She also participated in the landings at Ibiza and in the failed Invasion of Majorca, as well as in the Battle of Cape Cherchell, while under the command of Captain Alberto Bayo.