"Cambrian", the fourth ship of her name in the Royal Navy, was laid down by Pembroke Dockyard in Pembroke Dock, Wales, on 8 December 1914, launched on 3 March 1916, and completed in May 1916. She was commissioned into service that same month and was assigned to the 4th Light Cruiser Squadron of the Grand Fleet in which she served through the end of World War I and until 1919. The squadron was generally tasked with screening the battleships of the Grand Fleet during the war. The ship did not participate in the inconclusive Action of 19 August 1916 with the rest of her squadron. The squadron was briefly detached from the Grand Fleet in March 1917 to fruitlessly patrol off the Norwegian coast when news of a blockade runner was received by the Admiralty.