Sea Life Park is a marine park and aquarium near Makapu'u, with tanks, animal shows, and paid encounter programmes. It is a polished family attraction rather than a wild nature experience, but the coastal setting is dramatic and it can be useful with children after beach and lookout stops on the east side of Oahu.
Animal encounters are expensive, so check current prices before you build a day around them. Even without the add-ons, the park pairs easily with Makapu'u Point, Sandy Beach, and the drive along Kalanianaole Highway.