I went to Costa Maya as part as the hurricane blown 10 night cruise. The ship docked out an outside mall that I heard was specifically built for cruise ships. It was fun for awhile but you see a lot of the same stuff sold over and over again. Still, it was fun to look around and find the hidden treasures. We found a man who paints tiles with his finger - beach scenes, tropical scenes. We thought it was neat and bought a bunch of those for presents. Lots of silver.
They also have a restuarant and bar, big pool, and a small beach with chairs and umbrellas. A bunch of us braved the climb over sharp rocks and swam and snorkled but I heard later that there was a sign not to do that. I also heard that there are shows but we missed them.
It is totally different than approaching GC or Coz because the land is totally green, not filled with neon lights, cars and buildings. I would have like to leave the mall area but since it was an unexpected stop,there was no time to plan and see what else there might be to do. There was a place to hire tours and taxis. Disney did run excursions and some people did venture out to the fishing village.
I would go again. It was nice because the ship was literally right there and there was a trolley that drove people up and down the dock. The water was incredible.