Carnival used to have a cruise that could be boarded and de-boarded in Santo Domingo. The cruise actually started and ended in Puerto Rico, but due to many canadiens who did not want to go through the US territories, a provision was made for them to purchase cruises through the DR. After leaving the DR and arriving in PR you had to leave the ship for 6-8 hours for security and maintenence, then re-board. The rest of the trip was normal. You should check with the cruise lines to see if this type of service is available from the ships that stop in La Romana.