Glengyle was able to make good speed on long ocean voyages to operational areas and then with its landing craft, transport assault infantry, vehicles and stores to defended shores.

In 1938, whilst Glengyle and her sisters, Glenearn, Glenroy, and Breconshire were being built, the Inter-Service Training and Development Centre determined that they would be ideal for infantry landing ships.

To keep secret the presence of an infantry landing ship, Glengyle was disguised as a tanker and on 19 August transported The Essex Scottish Regiment to White Beach.

She returned to the Mediterranean in November, where she was used to transport US troops for the Operation Torch landings and was also involved in the Allied invasion of Sicily in 1943, during which Admiral Philip Vian briefly commanded a squadron aboard her.

She was at Trincomalee in August, and in company with Llanstephan Castle (Union-Castle Line), she transported 3 Commando Brigade to Hong Kong, arriving shortly after the end of the war.