What role did naval warfare play in World War 2?

In the European theater, naval warfare primarily involved the transportation of troops and equipment; bringing war materials to England, and transporting armies to Africa and Europe.

In the Pacific theater, the war itself was primarily a naval conflict. The Japanese aicraft launched from aircraft carriers made the initial strike against Pearl Harbor. In May 1942, in the first naval battle in which the opposing naval forces never saw each other in the Battle of the Coral Sea, carrier-based aircraft prevented the Japanese invasion of Australia. In June 1942, at the Battle of Midway, American carrier-based aircraft sank four Japanese carriers and broke the back of the Japanese Navy. From then until the end of the war, the Japanese were retreating.

As American forces advanced in island-hopping advances using amphibious assault, the American Marines and Army grew closer to the homeland of Japan. After the assault on Guam and Saipan, American air bases were built close enough to Japan to begin continuous bombardment of the Japanese factories and cities.