Just got back from Varadero and to clarify...
The Catamaran trip with the Dolphin swim in the ocean pen is a slightly shorter catamaran ride leaving from the end of Varadero.
The longer Seafari trip had a Dolphin show at the end of the trip at the Dolpharium in Varadero. The Catamran ride itself is longer.
Both stop and have lunch at Cayo Blanco.