I did a slightly different package last week, and it was great.
120 CUC. You take a Catamaran that holds 30 people, and do a nice cruise up to the reef at Paradisus, for 30 min of snorkelling. Then a light snack, on the way to the Dolphinarium. Guides will suggest you take some beer with you to the dolphinarium, because you'd have to pay there.
We were in 2 groups of 6 in the water, and you spend about 20 min with the dolphins. They now charge an extra 10 CUC (not included) if you want to do the fin ride, or the water ski, with the dolphins.
Then we had a big lobster lunch, and did a tour of the rest of the facility. There are now 2 baby dolphins in seperate pens. One is about 4 months old, and the other is only five weeks.
Back to the Catamaran, to sail back to the marina, and a short bus ride, back to the hotel.