Ko'olina is known for its lagoons and its proximity to Mickey Mouse.  The free diving here is real close to shore but a dive boat is preferable to reach some of the more interesting dive spots.  Plenty of sea turtle, rays, octopus and tropical fish to really make your day.   There are a lot of hidden coves and tidal pools to explore here.  This is a great place to bring a family and keep tabs on everyone easily.  Farther up the coast is Electric Beach famous for the heated water coming out of the ginormous pipe from the Electric Company nearby.  Be careful the water shooting out of the pipe will give you quite a ride.