As the Allies were preparing for the invasion of France on 6 June 1944, Combined Operation Headquarters assigned the 10th Destroyer Flotilla the task of eliminating German destroyers in the English Channel and Bay of Biscay. The flotilla was composed of Royal Canadian Navy (RCN) and Royal Navy (RN) vessels: the destroyers HMCS Haida (RCN), Huron (RCN), Athabaskan (RCN), HMS Tartar (RN), Eskimo (RN), Ashanti (RN), and Nubian (RN). This formidable group was bolstered with the addition of the RN cruisers Bellona and Black Prince. British Vice-Admiral Leatham commanded the flotilla. Throughout April, the 10th Destroyer Flotilla staged several aggressive patrols in the English Channel. By 24 April, the Haida, Athabaskan, and Huron had conducted 19 night missions.
The three RCN destroyers, supported by the RN cruiser Black Prince and the destroyer Ashanti, scoured the English Channel for German destroyers from 25 to 28 April 1944. The Haida and Athabaskan sank the German destroyer T-29 on the night of 25 April. As the group was returning to Plymouth, a port city in the south of England, the Ashanti and Huron collided. While both destroyers sustained only light damage, they would remain in port for repairs.
On the night of 28-29 April 1944, the Haida, captained by Commander Harry DeWolf, and the Athabaskan, commanded by Lieutenant-Commander J.H. Stubbs, were patrolling the coast of northern France near the harbour of Brest. At 3:30 a.m., the two Canadian destroyers encountered the German destroyers T-24 and T-27. Commander DeWolf immediately gave the order to attack. As the two RCN ships closed with the enemy, the Athabaskan was torpedoed by one of the German destroyers. Although the Athabaskan gun and torpedo crews continued to fire, the destroyer was clearly sinking. Lieutenant-Commander Stubbs gave the order to abandon ship.
The two German destroyers now concentrated their fire on the Haida, but Commander DeWolf continued his attack run. The gun crews of the Haida targeted T-27, and, in a matter of minutes, the German ship was in flames. As the captain of T-27 beached his ship, the Haida turned its guns on T-24 as it attempted to pick up Athabaskans survivors. The RCN destroyer inflicted heavy damage on T-24, and the German ship retreated northward.
The Haida managed to pick up 44 survivors, but 128 Canadian seamen were lost, including Lieutenant-Commander Stubbs. Some 83 of the Athabaskan's crew managed to swim ashore on the French coast and became prisoners of war.
During its operations in April, the 10th Destroyer Flotilla had sunk 3 destroyers, 1 U-boat, 31 other enemy ships, and damaged 17 others. The RCN destroyer HMCS Haida had accounted for 2 destroyers, 1 U-boat, and 15 other German ships.