i go out snorkeling in a kayak a lot. head to the reef, wander a bit north and south to find buoys, tie to them. great way to do it. i go out from most northern resorts, portofino, azul, mata chica, etc. real close way up north, but mexico rocks is maybe ten minutes from portofino. probably less. its in the middle, not out by the reef. its a good pull out there like pedro2 says. i ALWAYS take a waterproof bag also

you can also ask your resort about buoy locations near to them.