Following the start of World War I in July 1914, Hela was brought back to active duty and assigned to IV Scouting Group.
The unit was tasked with supporting the German torpedo boats that formed the outer ring of coastal scouting patrols in the German Bight.
She was modified slightly between 13 and 16 August, having a third 8.8 cm gun installed.
Hela was stationed to the northeast of Helgoland, along with the cruiser Stettin.

On 28 August, British cruisers and destroyers from the Harwich Force surprised and attacked the German patrol line, resulting in the Battle of Helgoland Bight.
Hela's commander received reports of the fighting and turned east to reinforce the vessels engaged in the action.
While en route, the ship received a contradictory report that stated that the British vessels were retreating, leading now Fregattenkapitän (Frigate Captain) Wolfram to reverse course and return to his assigned location.
As a result, she was not engaged in the action.
Later that night, she regrouped with the cruisers Kolberg and München to provide cover for the remaining torpedo boats and reestablish the Bight patrol line.

Two weeks later, on the morning of 13 September, Hela was attacked six miles southwest of Helgoland by the British submarine HMS E9 under command of the future Admiral Max Horton.
Hela was conducting a training exercise at the time; the area around Helgoland was presumed safe from British submarines.
After surfacing, E9 spotted the German cruiser and immediately re-submerged to fire two of her torpedoes, one of which struck Hela's stern.
After 15 minutes, E9 rose to periscope depth to inspect the scene.
The British submarine found Hela sinking.
Within another 15 minutes, Hela had slipped beneath the waves.
Despite the speed with which the ship sank, her entire crew, with the exception of two sailors, were rescued from the sea by the U-boat U-18 and one of the coastal patrol vessels.

Hela was the first German ship sunk by a British submarine in the war.
As a result of her loss, all German ships conducting training exercises were moved to the Baltic Sea to prevent further such sinkings.
One of her 8.8 cm guns was retrieved from the wreck and is now preserved at Fort Kugelbake in Cuxhaven.
Following the start of World War I in July 1914, Hela was brought back to active duty and assigned to IV Scouting Group. The unit was tasked with supporting the German torpedo boats that formed the outer ring of coastal scouting patrols in the German Bight. She was modified slightly between 13 and 16 August, having a third 8.8 cm gun installed. Hela was stationed to the northeast of Helgoland, along with the cruiser Stettin. 
On 28 August, British cruisers and destroyers from the Harwich Force surprised and attacked the German patrol line, resulting in the Battle of Helgoland Bight. Hela's commander received reports of the fighting and turned east to reinforce the vessels engaged in the action. While en route, the ship received a contradictory report that stated that the British vessels were retreating, leading now Fregattenkapitän (Frigate Captain) Wolfram to reverse course and return to his assigned location. As a result, she was not engaged in the action. Later that night, she regrouped with the cruisers Kolberg and München to provide cover for the remaining torpedo boats and reestablish the Bight patrol line.
Two weeks later, on the morning of 13 September, Hela was attacked six miles southwest of Helgoland by the British submarine HMS E9 under command of the future Admiral Max Horton. Hela was conducting a training exercise at the time; the area around Helgoland was presumed safe from British submarines. After surfacing, E9 spotted the German cruiser and immediately re-submerged to fire two of her torpedoes, one of which struck Hela's stern. After 15 minutes, E9 rose to periscope depth to inspect the scene. The British submarine found Hela sinking. Within another 15 minutes, Hela had slipped beneath the waves. Despite the speed with which the ship sank, her entire crew, with the exception of two sailors, were rescued from the sea by the U-boat U-18 and one of the coastal patrol vessels.
Hela was the first German ship sunk by a British submarine in the war. As a result of her loss, all German ships conducting training exercises were moved to the Baltic Sea to prevent further such sinkings. One of her 8.8 cm guns was retrieved from the wreck and is now preserved at Fort Kugelbake in Cuxhaven.
SMS Hela