Undaunted was powered by four Brown-Curtis steam turbines, each driving one propeller shaft, which produced a total of 40,000 indicated horsepower (30,000 kW).

The turbines used steam generated by eight Yarrow boilers which gave her a speed of about 28.5 knots (52.8 km/h; 32.8 mph).

On commissioning she was assigned as the leader of the 3rd Destroyer Flotilla of the Harwich Force, guarding the eastern approaches to the English Channel.

On 28 August 1914, Undaunted took part in the Battle of Heligoland Bight, and on 17 October 1914 she was involved in an action off the Dutch island of Texel with German torpedo boats.

She survived to see the end of the First World War, and was sold for scrap on 9 April 1923 to Cashmore, of Newport.