In 1940 the Llandaff Castle carried the first child evacuees to South Africa and was then requisitioned by the Admiralty as troopship. She brought troops to East Africa for the Abyssinian campaign and to the Middle East. Early 1942 extensively converted to carry 1150 soldiers for landings off enemy held coasts. On 5 May 1942, she took part in Operation Ironclad, the landings at the Vichy-French port Diego Suarez on Madagascar.

At 17.29 hours on 30 Nov 1942 the unescorted Llandaff Castle (Master Cornwallis Jasper Clutterbuck, OBE) was hit by two torpedoes from U-177 southeast of Lourenço Marques. The ship broke in two and sank after being hit by two coups de grâce at 17.47 and 18.09 hours. On board were 150 passengers including six Soviet diplomats with wives and children and 70 military officers with families. Three crew members were lost. The U-boat surfaced to question the survivors and as Gysae asked for the name of the ship voices replied Hardship and Queen Mary. He then asked if there were any wounded he was told that they were only wet so, amused, he left the area. The master, 155 crew members, four gunners and 150 passengers were picked up on 2 December by HMS Catterick (L 81) (Lt A. Tyson, RN) and landed at Durban.