On the outbreak of the First World War she was stationed in the Far East on the China and Pacific station, being involved in operations during the Shanghai Rebellion in 1913, that had arisen as a result of the Xinhai Revolution that had broken out two years earlier. When war broke out she bombarded Yap, prior to deploying to Valparaíso to search for the armed merchant raiderPrinz Eitel Friedrich. In January 1916, Newcastle captured the German ship Mazatlan. From November 1916 she was under the command of Captain Aubrey Smith In 1917 she was reassigned to the East Indies and in 1918 she was again moved to operate off South America. After an uneventful war service in comparison with her sisters, Newcastle was sold for scrapping on 9 May 1921 to the breaking firm of Ward. She arrived at the yards at Lelant on 3 May 1923 to be broken up.