In the years immediately before war was declared the Inter-Service Training and Development Centre sought to identify ships suitable to carry Army and Royal Marine formations being employed in amphibious operations.

By June 1940, Glengyle, Glenearn, and Glenroy were under conversion to LSI(L)s. The Admiralty insisted on keeping Breconshire in a fast cargo configuration, so the ISTDC consulted the Director of Naval Construction about suitable requisitioned ships.

[7] During April and June 1940, the Glens underwent further conversion into LSIs capable of transporting an embarked force of up to 34 officers and 663 other ranks and carrying 12 LCAs on Welin-McLachan davits and 1 LCM(1) stored in chocks on deck and launched by 30-ton derricks.

The only vital alterations to the 18 knot Glengyle and her sisters, Glenroy and Glenearn, were to assure davits strong enough to lower fully loaded LCAs, and to provide accommodation for the army units to be transported.

The rebuilding, which took place at Esquimalt and Vancouver, was completed in December 1943 and shortly after re-commissioning, she left for the United Kingdom via Panama canal and New York City, under Captain T.D.

In Australia in mid-1942, HMAS Manoora, an ocean liner that had been converted to armed merchant cruiser, was marked for conversion into the Royal Australian Navy's first landing ship, infantry at Garden Island Dockyard.

[16] The Supermarine Walrus amphibian aircraft was removed, and the ship was modified to carry US manufactured landing craft: 17 LCVPs, and two LCM(3)s.[17][18] Manoora was initially able to accommodate 850 soldiers, but later modifications increased this to 1,250.

[19] The ship was recommissioned on 2 February 1943 with the pennant number C77, and after spending six months on amphibious warfare training in Port Phillip, was deployed to New Guinea.

[20] In the United States, a commercial hull was put in war production by the Maritime Commission; the C1-S-AY1 subtype of thirteen ships built by the Consolidated Steel Corporation, were modified for use as LSI(L)s under lend-lease.

[22] Early landing ships were fitted with Welin-McLachlin davits – these being generally in use in the Merchant Navy for standard 99 man lifeboats.