While in Cozumel two years ago we did the dolphin encounter at Chankanaab. It was amazing! The park itself is beautiful, so much to do. I kept stalking the dolphin discovery website weekly because they constantly change their coupons until one day I landed a coupon for 50% off. It is a 10 minute cab ride from the port. Once you pay for a dolphin activity, entrance to the rest of the park is included. I have not been to Dolphinaris but I definitely recommend Chankanaab. The pictures they take of you (you cannot take any of your own) are highway robbery. The only reason we ended up purchasing was because we were a large group and were able to split the cost enough where it was almost reasonable. Otherwise you're looking at like $30/picture or $200 plus for a CD depending on how many people there are.