Catalina Island is a small beach island off the coast of the Dominican Republic, Island of Hispanola... near the town of LaRomana. As private islands go, it is quite nice... with the usual popouri of water sports, beach, barbeque and stands selling local stuff. The Dominicans put on lots of dancing demonstrations and the ship's guests are invited to join. It is really quite nice. Yes, Celebrity uses is too, on rare occasions.
One of the best kept secrets in the Caribbean... you can take a shore excursion from either Costa Ships at that stop to Santo Domingo, the capitol city of the Dominican Republic. It is an all day tour... they take you from the ship by launch to the town of LaRomana, where you board buses for the trip to Santo Domingo. It reminds me of visiting a South American City... lots of interesting historic sites (they first mayor of Santo Domingo was Christopher Columbus' son... to put it in perspective). Nice shopping... NO tee shirt shops or liquor stores... really an untouched location. It is possibly the most interesting shore excursion in the Eastern Caribbean (on a 7 night jaunt from S. Florida) and includes lunch.