I've never done a swim with the dolphins in any port, but if they do offer the excursion do it. It was the most awesome experience I've ever had. We did ours in Cozumel (pre-hurricane). I have the video. Make sure you do a swim and not an encounter. You get to actually interact and be in the water with the dolphins when you do a swim. It is a totally amazing experience. Hope you have a wonderful cruise. You're visiting some great islands.