When did Pearl Harbor become a naval base?
Naval Station, Honolulu officially came into being on 17 November 1899. There had been much discussion and several treaties were signed between the King of Hawaii and the US prior to that. The location had served off and on as a coaling station for the US Navy over the previous 20 or so years.
Pearl Harbor is a lagoon harbor on the island of Oahu that is a United States Navy deep-water naval base. It was attacked by the Empire of Japan on December 7, 1941, resulting in the United States' entry into World War II. Today, there is the USS Arizona Memorial and part of the Pearl Harbor naval base remaining.