On 21 November 1912, she took part in the Battle of Kaliakra. The Ottoman force sent to Varna with the mission of preventing Bulgarian attacks on Ottoman merchant ships loaded with ammunition and, if possible, destroying Bulgarian torpedo boats, consisted of , and Yarhisar; however Basra broke down and was replaced by the torpedo boat Berkefşan. The ships sailed into the Black Sea at 09:00 on the morning of November 20. After the repair of the broken down Berkefşan, she joined these two ships at 13:00 . At a meeting held at 16:50 on board Hamidiye, she ordered Yarhisar to take position south of Varna and Berkefşan 8 miles north of Varna, to observe the Bulgarian torpedo boats entering and leaving the harbor and to attack the torpedo boats. After the meeting, the ships departed for Varna at 17:50 and dispersed at 20:00, heading for their duty areas. Yarhisar was in position at 21.30, followed by Berkefshan at 00:00 as Hamidiye was sailing towards Varna. Meanwhile, four Bulgarian torpedo boats had been patrolling en masse outside Varna harbor since 22:20. At 00:40, in the battle that started between the Bulgarian torpedo boats and Hamidiye, she was damaged. Meanwhile, Yarhisar, seeing the battle to the north of her, remained in her duty area until 05:30, then went to the aid of Hamidiye. Despite the damage Hamidiye received, she did not sink thanks to the successful work of the crew, but she was unable to continue her surveillance of Varna and decided to return to Constantinople, calling the torpedo cruiser Berk-i Satvet to the area, thinking that Yarhisar and Berkefşan would be insufficient for the mission. Upon this message, Berk-i Satvet abandoned its mission in Constanta and immediately set off. Berkefşan and Berk-i Satvet patrolled in front of the cape until morning. At 08:00 on November 21, when Yarhisar arrived at the rendezvous point and could not find Hamidiye and Berkefşan, the ship's commander decided to scout Varna. She made four passes within of the city and was not subjected to fire from the shore or Bulgarian torpedo boats. Due to a storm, she sailed for Istanbul at 17:00. Meanwhile, the commander of Berk-i Satvet, thinking that his mission to watch Varna was over, sailed for Constanta and sent Berkefşan to Istanbul.
