She was launched on 9 July 1940 from the Leith Docks on the Firth of Forth and named after the genus of flowering plants including Carnation, Pink, and Sweet William.

The ship escorted trade convoys between Newfoundland and the Western Approaches through the Battle of the Atlantic wolf pack attacks of the winter of 1942–43.

[2][3][4] The "corvette" designation was created by the French in the 19th century as a class of small warships; the Royal Navy borrowed the term for a period but discontinued its use in 1877.

[5] During the hurried preparations for war in the late 1930s, Winston Churchill reactivated the corvette class, needing a name for smaller ships used in an escort capacity, in this case based on a whaling ship design.

Dianthus was assigned to MOEF group A3 after yard overhaul to repair damage from the ramming collision.