HMS Blackwater was a Laird-type River-class destroyer ordered by the Royal Navy under the 1902–1903 Naval Estimates.

She was laid down on 27 August 1902 at the Cammell Laird shipyard at Birkenhead and launched on 25 July 1903.

After commissioning she was assigned to the East Coast Destroyer Flotilla of the 1st Fleet and based at Harwich.

On 27 April 1908 the Eastern Flotilla departed Harwich for live fire and night manoeuvres.

On 6 April 1909 Blackwater collided with the merchantman SS Hero, and sank off Dungeness in the English Channel at position 50°55′21″N 1°6′10″E / 50.92250°N 1.10278°E / 50.92250; 1.10278.