You would want to take water taxi or land taxi. I have only done land, you will find them all over, takes about 10 to 15 mins by cab from the port. Atlantis is the only thing really worth going out of your way for. It's very fun but pricey and I plan to skip it on my next cruise as getting there and back and enjoying it takes the whole day. I know your supposed to have a special pass you do the aquarium but I never saw anyone checking. My advice is if your not super big on waterparks(because the beach at Atlantis is really not worth it). Get off the boat, maybe do a little shopping and grab a bottle of wine to bring back or a six pack, and get back on the boat earlier to enjoy the pool while crowds are down
We took the water taxi over to Atlantis and then paid to walk through The Dig, which is a small-ish aquarium. We walked the beach, which at that time had very deep powdery sand, but did not sit there. I have heard that Atlantis cut down the number of "walk-up" items you can pay for, trying to force people to book overpriced excursions through the cruise ships, but I don't know if that is accurate right now or not. Certainly they will let you spend your cash on their food ($$$) or casino. It was neat to walk around the complex and check out the level of detail.
Walking to Atlantis would be tough because there is a large bridge that, from my understanding, is not very pedestrian friendly.
Both of the cruises we've taken have stopped in Nassau, and we haven't left the ship either time. Our next cruise does not stop there and we likely won't look to book an itinerary that does stop there in the future, because it holds zero interest for us.
If you haven't been there I think it's worth jumping in a cab and checking out Atlantis. It's not a big expense and only takes a couple hours of your day if that. I can't imagine stopping at any port I haven't been to and not getting off the ship. At least you can say you've seen it.
I envision us getting off and walking around near the port for an hour or two, being back on the ship for lunch, then enjoying the pool, etc. in the afternoon. I think this will satisfy our daughter that she can say she's been there while still spending the majority of our day on the ship.
That is what I have done. No excursions, nothing that requires a cab, or a car, or a scooter, or a boat. Just get off, walk around, do some shopping if you find something that interests you, and then back on the boar.
They do have some interestinf liquor drinks at Pirate Republic too. They have a pirate tour and free wifi as well. We went last year at this time, but the “pirate had called in sick” and the wifi was down, so we didn’t stay long. It has all thr makings to be a great place. We could see it from our porthole on the ship
I would gladly trade that Nassau stop for a 2nd day at Castaway Cay. Our 1st DCL was a 3 nighter. I had booked an excursion, but cancelled before we left Port Canaveral. Got off, walked around for an hour or so (so my daughter could say she'd visited a foreign country) and got back on board. Spent the afternoon in the spa. We no longer get off ship if there's a stop at Nassau, but use that as a day to relax, get a one day spa pass, etc.