It would help to know if you are staying in Oahu before the cruise or if you are flying in the day of the cruise. We stayed in Waikiki three days prior to the cruise and on the morning of the cruise we walked over to the Waikiki Aquarium and spend about an hour there. Since it is across the street from Kapiolani Park, we took a leisurely walk through the park. We opted to get to the ship early and use the day as a sea day to prepare for the hectic pace of the cruise.
After we disembarked at the end of the cruise, we checked our luggage and walked over to Iolani Palace where we had booked a tour.