Discover the best of Hawaii for less with top-rated Oahu tours and excursions on Viator. Take the best-selling Grand Circle Island tour, snorkel with turtles in Waikiki, visit the USS Arizona Memorial at Pearl Harbor, or hike Diamond Head with tickets and shuttle included. You can also dive into an Atlantis submarine adventure, explore the Kualoa Ranch movie sites, or enjoy a Waikiki luau and a golden hour sunset cruise. The Grand Circle Island tour is rated 5.0 by nearly 20,000 travelers, and almost every tour includes free cancellation. Prices start from just $28 per person.