Canada officially entered the Second World War on September 10, 1939, and continued at war for nearly six years. The struggle involved virtually the whole country and made enormous demands on the Canadian people, whether they were involved in the actual fighting or remained on the home front to work in industry or farming to support the war effort.

Twenty short years after the Great War, Europe again stood on the brink of a mighty upheaval in the summer of 1939. Clouds of war were on the horizon, and Canada would again be called into the fight.

By the time the Second World War ended six years later, more than 1.1 million Canadians and Newfoundlanders — from a population of about 11 million — would serve in the military.

The human toll would be immense: 45,000 Canadian soldiers would die and another 54,000 would be wounded.

The first Canadian troops departed for Europe at the end of 1939.

Canadian pilots fought side-by-side with the British air force in repelling the German Luftwaffe's attacks on the U.K. in the summer of 1940. The Royal Canadian Air Force engaged in direct combat with enemy planes for the first time in the war.

When the Second World War broke out, the RCN was again the first into action. Indeed, it was the RCN that constituted the mainstay of the Canadian war effort for the first two years. Convoy escort work commenced immediately in September 1939, and from the spring of 1940 RCN destroyers participated in operations off the French coast, including the evacuation from the continent. The “Corvette Navy” of the RCNVR and the Battle of the Atlantic against the German U-boats are justifiably remembered as major accomplishments of the fifty-fold expansion of the RCN (from some 2000 all-ranks to nearly 100,000 by 1945), but that was not near the sum of the navy’s accomplishments. In 1941, with the fate of Britain uncertain and the US not yet committed, the possible requirement to defend home waters and the growing competence of the RCN argued for the building of a strong national navy. Therefore, while defeat of the U-boats remained a priority, the Canadian government ordered the concurrent acquisition of cruisers and powerful Tribal class destroyers in addition to the scores of anti-submarine corvettes and other escorts. As well, the naval college was re-opened to ensure the training of officers in Canada. By 1943, allied circumstances had improved considerably, but a new impetus existed for the continuation of a viable Canadian fleet. Recognising the limits of the pre-war policy of isolationism, the Department of External Affairs was developing a commitment to collective security as the basis for the post-war international order. In those days, only a navy could provide military force with global reach and, by 1945, the plans for the post-war RCN envisioned a carrier task force on each coast.

The Second World War[1] officially began on 1 September 1939, with the German invasion of Poland. Britain and France declared war on the Nazi Third Reich, two days later, on 3 September 1939. Seven days later, on 10 September 1939, Canada likewise declared war on Germany, the country's first independent declaration of war[2] and the beginning of Canada's participation in the largest combined national effort in its history. By the war's end, over 1 million citizens would serve in military uniform (out of a prewar population of 11 million) and Canada would possess the fourth-largest air force and fifth-largest naval surface fleet in the world. Originally it was thought that Canada had the third-largest navy in the world, but with the fall of the Soviet Union new data based on Japan and the USSR came to light and it was found to be incorrect.[3]