Isla Catalina is a small uninhabited island about 20 minutes by boat from La Romana, ringed with reefs and calm blue water. It is a popular stop for snorkellers and divers from the Casa de Campo resort and from La Romana marina. The north side has the best coral, while the south-facing beach is calmer for swimming and sunbathing.
The island has no permanent facilities, so day trips come with everything provided — snorkelling gear, lunch, drinks. Most operators run half-day trips that combine a stop at Catalina with a swim at the sandbar before returning. Because it is closer than Saona and the boat ride shorter, it works well as a morning or afternoon excursion rather than a full day.