Hanauma Bay is must do for your Oahu island itinerary. It is one of the premier destinations if you want to get acquainted with a plethora of fish and marine life and offers an overall great experience for people of all ages. It is Voted the #1 beach in the united states for 2016! There are many tour operators out there that will bring you here on a tour. I suggest getting there yourself or with the official Hanauma bay state park preserve operator so that you don’t have to rush based on the tour guide time. When you get there there is a educational video on how to help take care of the park and wildlife. After the video there is a small museum type educational experience and then you descend down into the bay. Set up your spot and go snorkeling or diving. You can see a ton of fish and coral in very shallow water. It is a beautiful setting and should not be missed on your Oahu vacation.