When World War I broke out in August 1914, Jupiter was transferred to the 7th Battle Squadron of the Channel Fleet.
During this service, she covered the passage of the British Expeditionary Force from England to France in September 1914.
In late October 1914, Jupiter was reassigned to serve alongside her sister ship Majestic as a guard ship at the Nore.
On 3 November 1914, Jupiter and Majestic left the Nore and relieved their sister ships Hannibal and Magnificent of guard ship duty on the Humber.
In December 1914, Jupiter moved on to guard ship duty on the Tyne.
On 5 February 1915, Jupiter was detached from her guard ship duty to serve temporarily as an icebreaker at Arkhangelsk, Russia, while the regular icebreaker there was under refit.
In this duty, Jupiter made history by becoming the first ship ever to get through the ice into Arkhangelsk during the winter; her February arrival was the earliest in history there.

Jupiter left Arkhangelsk in May 1915 to return to the Channel Fleet, and was paid off at Birkenhead on 19 May 1915.
She then began a refit by Cammell Laird there that lasted until August 1915.
Her refit completed, Jupiter was commissioned at Birkenhead on 12 August 1915 for service in the Mediterranean Sea on the Suez Canal Patrol.
On 21 October 1915, she was transferred to the Red Sea to become guard ship at Aden and flagship of the Senior Naval Officer, Red Sea Patrol.
She was relieved of flagship duty by the troopship RIM Northbrook of the Royal Indian Marine on 9 December 1915 and returned to the Suez Canal Patrol for Mediterranean service.
This lasted from April to November 1916, with a home port in Port Said, Egypt.

Jupiter left Egypt on 22 November 1916 and returned to the United Kingdom, where she was paid off at Devonport to provide crews for antisubmarine vessels.
She remained at Devonport until April 1919, in commission as a special service vessel and auxiliary patrol ship until February 1918, when she was again paid off.
After that she became an accommodation ship.
In April 1919, Jupiter became the first Majestic-class ship to be placed on the disposal list.
She was sold for scrapping on 15 January 1920, and on 11 March 1920 was towed from Chatham to Blyth to be scrapped.
When World War I broke out in August 1914, Jupiter was transferred to the 7th Battle Squadron of the Channel Fleet. During this service, she covered the passage of the British Expeditionary Force from England to France in September 1914. In late October 1914, Jupiter was reassigned to serve alongside her sister ship Majestic as a guard ship at the Nore. On 3 November 1914, Jupiter and Majestic left the Nore and relieved their sister ships Hannibal and Magnificent of guard ship duty on the Humber. In December 1914, Jupiter moved on to guard ship duty on the Tyne. On 5 February 1915, Jupiter was detached from her guard ship duty to serve temporarily as an icebreaker at Arkhangelsk, Russia, while the regular icebreaker there was under refit. In this duty, Jupiter made history by becoming the first ship ever to get through the ice into Arkhangelsk during the winter; her February arrival was the earliest in history there.
Jupiter left Arkhangelsk in May 1915 to return to the Channel Fleet, and was paid off at Birkenhead on 19 May 1915. She then began a refit by Cammell Laird there that lasted until August 1915. Her refit completed, Jupiter was commissioned at Birkenhead on 12 August 1915 for service in the Mediterranean Sea on the Suez Canal Patrol. On 21 October 1915, she was transferred to the Red Sea to become guard ship at Aden and flagship of the Senior Naval Officer, Red Sea Patrol. She was relieved of flagship duty by the troopship RIM Northbrook of the Royal Indian Marine on 9 December 1915 and returned to the Suez Canal Patrol for Mediterranean service. This lasted from April to November 1916, with a home port in Port Said, Egypt.
Jupiter left Egypt on 22 November 1916 and returned to the United Kingdom, where she was paid off at Devonport to provide crews for antisubmarine vessels. She remained at Devonport until April 1919, in commission as a special service vessel and auxiliary patrol ship until February 1918, when she was again paid off. After that she became an accommodation ship. In April 1919, Jupiter became the first Majestic-class ship to be placed on the disposal list. She was sold for scrapping on 15 January 1920, and on 11 March 1920 was towed from Chatham to Blyth to be scrapped.
HMS Jupiter (1895)