What is the number one thing to do in Oahu?

Most visitors rank Pearl Harbor as Oahu's unmissable experience, but for Hawaii authenticity, a luau comes close. Chief's Luau at Sea Life Park ($130–220) includes an imu ceremony, hula performances, and open bar — the best on the island. For adventure, helicopter tours from Magnum Helicopters ($380+) reveal the Ko'olau Mountains and North Shore from above. The North Shore itself is essential: Banzai Pipeline, Haleiwa town, and roadside shrimp trucks make for a full day. Snorkeling at Hanauma Bay, a protected marine reserve, is the best free activity on the island. Book tours at least a week ahead — popular options sell out fast, especially December through March.