Just returned from Costa Maya-- our ship stopped from 8-2pm.
We walked (30 min.) south to the town of Mahahual (or take a taxi for $3) It was AWESOME!! We stopped at the first bar (at north end) called Corona del Mar. Beautiful beach--great snorkeling right in front of the bar and free use of kayaks if you eat/drink there.
The owner--Jesus Agca is great--fun to chat with!!
The whole town is really cool to walk through--inexpensive and authentic mexico!!