We were in Costa Maya last Sept. There was still some hurricane damage. Our first visit to this port. Did not do any excursions. Just shopped, and watched the dolphins. The dolphin encounter excursion is near the enterance to the port.
If you purchase a picture from the guy that paints with spray cans of paint, take the picture with you. We had him mail ours, and it arrived with picture/container damaged. Still waiting for the replacement he promised us.
Hope you enjoy your cruise on the Dream, and also hope Mahogany Bay is one of your stops