Operation Olympic was the first phase of Operation Downfall, the planned Allied invasion of Japan.
Olympic was intended to begin on November 1, 1945, with landings on southern Kyushu, Japan's southernmost major home island. The Allies planned to capture territory and airfields there, using Okinawa as a staging area. Those bases would then support the second phase, Operation Coronet, aimed at the Kantō Plain near Tokyo.
The planned naval force for Olympic would have been immense. The operation was expected to include 42 aircraft carriers, 24 battleships, and roughly 400 destroyers and destroyer escorts. Fourteen U.S. divisions and additional forces were scheduled for the initial landings.
Olympic never took place because Japan surrendered in August 1945. “Operation Majestic” is sometimes associated with Olympic because that replacement codename was adopted after the original name was compromised. Operation Pastel was a related deception plan, not the invasion itself, and Coronet was the later phase of Downfall.