"Suffren" was originally intended to refit at the naval base at Bizerte, but the location was switched when the dockyard at Lorient informed the Naval Staff that it had room for her. On 15 November the ship departed to recoal at Bizerte which she reached on 18 November. She sailed on 20 November for Gibraltar; heavy weather en route delayed her arrival until 23 November. "Suffren" recoaled and departed Gibraltar the following day without an escort. On the morning of 26 November, roughly off the Portuguese coast near Lisbon, she was torpedoed by the German submarine , which was en route to the Austro-Hungarian naval base at Cattaro in the Adriatic Sea. The torpedo detonated a magazine and "Suffren" sank within seconds, taking her entire crew of 648 with her. "U-52" searched the scene, but found no survivors.