We just stayed in port during the day. There are a number of ways to get over to "Atlantis". You can actually see it from the ship, but it'd be a long, long hike to walk it. You can take a taxi from the pier, or even take a water taxi from the side of the pier as well. I don't know what the fare from the pier to the "Atlantis" is, but wouldn't think it'd be too much. I'd bet you can find any number of people who'll share a cab with you to keep the cost down, as "Atlantis" is one of the major attractions in Nassau.