[1] On 7 August 1941 the heavy cruiser USS Augusta carrying U.S. President Franklin D. Roosevelt arrived in the anchorage at Little Placentia Bay off the base.

The conference concluded the evening of 12 August 1941 with the British and American warships and their escorts passing in review before departing the area for their home ports.

Later that spring the Royal Navy established a small maintenance base at Argentia to service its ships involved in convoy escort groups operating out of Halifax, Sydney, St. John's and in the Gulf of Saint Lawrence.

In August 1943, Task Force 24 Flag Headquarters moved ashore to permanent facilities after having been housed aboard USS Prairie.

[6] In 1944, Argentia served as one of the two stopover bases for the refuelling, maintenance, and crew changes of the six United States Navy (USN) K-class blimps that made the first transatlantic crossings of non-rigid airships.

The two K-ships then flew for approximately 22 hours to Lages Field on Terceira Island in the Azores, the second stopover base for the transatlantic flights.

[7] These six blimps initially conducted nighttime anti-submarine warfare operations to complement the daytime missions flown by FAW-15 aircraft (PBYs and PB4Y-2) using magnetic anomaly detection to locate U-boats in the relatively shallow waters around the Strait of Gibraltar.

Later, ZP-14 K-ships conducted minespotting and minesweeping operations in key Mediterranean ports and various escort missions including that of the convoy carrying Franklin Roosevelt and Winston Churchill to the Yalta Conference in early 1945.

These guns were on shielded long-range carriages with reinforced concrete and earth bunkers housing magazines and fire control equipment.

[16] On 16 February 1942 the harbour defence units in Newfoundland were redesignated as components of the 24th Coast Artillery (Harbor Defense) (Composite) Regiment, the headquarters and two additional batteries of which arrived at Fort McAndrew from the US on 25 March 1942.

[15] By the end of 1942 the coast defence gun batteries in the Argentia area were as follows:[18][16] In March 1943 the 24th CA Regiment was reduced to a battalion.

[18] Following the war's end in August 1945, the first dependents of naval personnel were permitted to move to Argentia to live in permanent quarters on base.

During the Cold War, Argentia Naval Station became a key "node" in the Northwest Atlantic's SOSUS network, helping to detect Soviet nuclear submarines.

Associated with the DEW Line, radar picket ships such as USS Hissem used the base, and Lockheed WV-2 Warning Star aircraft used the airfield.

[20] In 1959 the United States Naval Facility (NAVFAC) Argentia was established as a Sound Surveillance System (SOSUS) shore terminal.

After the US Naval Station was decommissioned, the glider program was operated without facilities support until the airfield was occupied in 2004 for a Hydrometallurgy Demonstration Plant by INCO.