HMNB Portsmouth the military and naval units destined for Sword Beach on the Normandy coast as a part of Operation Overlord and the D-Day landings on 6 June 1944. Troops destined for each of the landing beaches left from Portsmouth aboard vessels such as the armed merchant cruisers HMCS "Prince Henry" and HMCS "Prince David", escorted by the Canadian destroyers HMCS "Algonquin" and "Sioux". The majority of the naval support for the operation left from Portsmouth, including the Mulberry Harbours. Boathouse 4 (built around the start of hostilities) contributed to the construction of landing craft and support vessels as well as more
Australian contribution to the Battle of Normandy (EATS), were stationed in the United Kingdom (UK) and took part in operations against Germany. The Australian Government had very little influence over where Australian graduates of EATS were posted, and many were assigned directly to British units. As of 6 June 1944, 1,816 Australian airmen (including 584 pilots) were posted to RAF squadrons. Many of the thousands of Australian ground crew in the UK at this time were also serving with RAF units. In addition, ten RAAF flying squadrons were stationed in the UK. These included one regular RAAF unit, No. 10 Squadron, and nine temporary "Article XV squadrons,"