Several years ago we did a dolphin swim at the Dolphin Discovery at Chankanaab National Park in Cozumel. It was really nice and we had a lot of fun. Disney offers different excursions there now than when we did it with them. We had to buy our own food, it was good. There is a lot to do at the park, so if you go there I would suggest you pick the earliest time so you have time afterwards to explore the park. We had about 3 hours after we were done with the dolphins and didn't get to see everything. I haven't been to Dolphinaris, but when I did my research it didn't seem to have as much to do there as Dolphin Discovery. We saw the sea lion show, went to the free tasting at the tequila hut, walked around the "ruins", ate lunch, had ice cream(we paid extra for food, I think now it's included), and played at the beach for a little bit. This was all included in the price we paid to do the excursion. I would do this excursion again. They have free lockers that you can fit a backpack/beachbag in, take towels from the ship. They also have showers(not private) so you can rinse off and a changing area.