HMS Fermoy was a Hunt-class minesweeper of the Aberdare sub-class built for the Royal Navy during World War I. Although she was under construction during the First World War, she was not completed in time to participate in combat operations. In 1941, she was severely damaged by German bombers and was subsequently scrapped.
The Aberdare sub-class were enlarged versions of the original Hunt-class ships with a more powerful armament. The ships displaced at normal load. They had a length between perpendiculars of and measured long overall. The Aberdares had a beam of and a draught of . The ships' complement consisted of 74 officers and ratings.
The ships had two vertical triple-expansion steam engines, each driving one shaft, using steam provided by two Yarrow boilers. The engines produced a total of and gave a maximum speed of . They carried a maximum of of coal which gave them a range of at .
The Aberdare sub-class was armed with a quick-firing (QF) gun forward of the bridge and a QF twelve-pounder (76.2 mm) anti-aircraft gun aft. Some ships were fitted with six- or three-pounder guns in lieu of the twelve-pounder.
HMS Fermoy was built by the Dundee Shipbuilding Company. By 1923 she had become the depot ship for the Submarine Periscope School at Portland and on 14 April Hugh Marrack was appointed in command.
She was bombed by Italian aircraft off Valletta, Malta, on 30 April 1941, then on 4 May 1941, and was written off as constructive total loss. She was eventually raised and sold for scrap.