8 mile loop. Most of the tourist activities are in the main town near Playa Norte. You can start there and head West to the Caribbean, then South - stay as close to the water as you can. 4 miles to the Southern tip of the island, and Mayan ruins - if you run early in the morning you can go right in free of charge. Then head back up the eastern shorline - don't miss the skyline view of Cancun across the water. Stop at the Soggy Peso across from the airport for a beer. You will need to carry water if you are doing more than one loop.