She remained in service during the First World War, where she was used for local patrol duties based at Plymouth and sank the German submarine UC-49 on 8 August 1918.

HMS Opossum, along with sister ships Sunfish and Ranger, was one of three destroyers ordered for the Royal Navy from Hawthorn Leslie on 7 February 1894 as part of the 1893–1894 Naval Estimates.

A total of 36 destroyers were ordered from 14 shipbuilders as part of the 1893–1894 Naval Estimates, all of which were required to reach a contract speed of 27 knots (50 km/h; 31 mph).

[17][18] On 30 August 1912 the Admiralty directed all destroyers were to be grouped into classes designated by letters based on contract speed and appearance.

[24] On the evening of 20 December 1917, Opossum, together with the destroyers Spitfire and Roebuck, five Motor Launches, four drifters and two fishing trawlers, was ordered to patrol Lyme Bay to search for a German submarine that had sunk three merchant ships the previous night.

After 20 seconds, the submarine descended under the surface again, with her bows at an angle of 50 degrees, and several more depth charges were dropped, bringing up oil and bubbles.

The next day, the wreck, which had been located by sweeps, was plastered with depth charges in order to break it up to confirm that the submarine had been sunk.