Commissioned into the Royal Navy in April or May (sources differ) 1916, "Canterbury" was attached to the 3rd Battle Squadron in the Grand Fleet, commanded by Captain Percy M. R. Royds, and participated in the Battle of Jutland on 31 May – 1 June 1916. From 1916 to 1918, she was assigned to the 5th Light Cruiser Squadron, operating as part of Harwich Force in the North Sea to defend the eastern approaches to the Strait of Dover and English Channel. On 5 June 1917, she and the light cruisers and sank the German torpedo boat "S 20" in the North Sea near the Shouwen Bank off Zeebrugge, Belgium. On St George's day, 23 April 1918, she was present at the great naval raid on Zeebrugge and Ostend.