The main reason the Japanese attacked Pearl Harbor on the Hawaiian Islands was to disable the United States' Pacific Fleet and prevent its interference in Japan's military operations in Southeast Asia. The Japanese considered the US presence in the Pacific as a threat to their expansionist ambitions in the region and saw the Pacific Fleet as their primary obstacle. By launching a surprise attack on Pearl Harbor, the Japanese aimed to cripple the US Navy's ability to respond swiftly and effectively, thus allowing them to establish uncontested control over Southeast Asia.
