On 26 March 1942 "Atherstone" sailed from Falmouth as part of Operation Chariot, the St Nazaire Raid. This was an amphibious assault on the port of St Nazaire in France with the objective of destroying the gates of the Normandie dock by ramming them with an explosive-packed destroyer, , and so prevent the dock's use by the . "Atherstone" and her sister ship escorted "Campbeltown" and the remainder of the strike force, towing the Motor Gun Boat "MGB 314" on the passage to St Nazaire. Early on 27 March, "Tynedale" sighted the , and the two escort destroyers attacked the U-boat. Although "U-593" survived the attack, the destroyers forced the U-Boat to stay submerged for several hours, preventing it from interfering with the operation.