Samphire was assigned to the 36th Escort Group and tasked with convoy escort operations between Liverpool and the Mediterranean Sea. On 21 December 1941, she successfully released depth charges with the British sloop Deptford resulting in the sinking of the German submarine U-567 in the North Atlantic northeast of the Azores. All 47 men on board the U-567 were killed. On 8 November 1942, she escorted USS Leedstown (AP-73) from the Mediterranean after she had been attacked by German aircraft, which hit the Leedstown with an aerial torpedo in the stern the day earlier. At 12:55 on 9 November, German aircraft attacked again, however Samphire shot down one attacker and then escorted the Leedstown to anchor near Cape Matifu, about 12 miles (19 km) from Algiers. On 14 December 1942, Samphire assisted in the rescue of nine survivors from the British merchant ship Edencrag, which had been torpedoed and sunk by the German submarine U-443 west of Algiers.
Sinking
Samphire was torpedoed and sunk on 30 January 1943 off Bougie, Algeria by the Italian submarine Platino. Samphire was escorting convoy TE-14 which was taking part in the North African campaign. The captain, two officers and 42 of the ship’s crew perished.