Dartmouth was laid down by Vickers at their Barrow shipyard on 19 February 1910, one of four Town-class protected cruisers ordered under the 1909–1910 Naval Estimates.

Machinery was the same as in the Bristol class, with 12 Yarrow boilers feeding Parsons steam turbines, driving four shafts.

[1][11][12] On the outbreak of the First World War, Dartmouth was docked at Bombay, but was soon returned to sea,[13] escorting a troop convoy from Karachi to Mombasa in Kenya and then taking part in the search for the German cruiser Königsberg.

[17][14] In January 1915, Dartmouth was reassigned to the 2nd Light Cruiser Squadron of the Grand Fleet but was detached to operate in the South Atlantic in the search for the commerce raider SMS Karlsruhe.

[22] In May 1915, Dartmouth was reassigned to the 8th Light Cruiser Squadron at Brindisi, supporting Italian forces in the Adriatic Sea.

[29] The two destroyers attacked an Italian convoy at about 03:30 Central European Time (CET), sinking the Italian destroyer Borea and the freighter Carrocio, with the main cruiser attack on the drifter line starting at about 04:20 CET, with 14 of the lightly armed drifters sunk and four more damaged.

The order to abandon ship was given but a small team volunteered to remain on board manning the pumps while the Dartmouth was towed to port.

Dartmouth was drydocked and repaired and went on to survive the war, following which she was assigned to the America and West Indies Station, based at the Royal Naval Dockyard, on Ireland Island in the Imperial fortress colony of Bermuda, where she was damaged by a hurricane in 1922, while simultaneously fighting a fire.