Sac Aktun is located four kilometers west of Tulum on the Coba Road. There is an attended parking area right at the road's edge, and a large sign that says "Gran Cenote" (the main entrance to the system).
After paying your entrance fee, you can suit up using convenient tables located right at the edge of the parking lot. You then walk a short distance to the edge of the cenote and descend a set of stairs. From here you walk to a large dock at the edge of the water, then jump in. That's all there is to it.
The main cavern at Gran Cenote is a popular cavern tour site. A gold line runs around the perimeter of the main cavern. The cavern area is so bright that you can shot video with out lights! This is one of the most decorated caverns in the area.
Depths in Gran Cenote seldom exceed 40 feet, and depths are fairly constant. There is no halocline anywhere in the cave.
CENOTE DOS OJOS
SISTEMA Dos Ojos is not only one of the world's largest underwater cave complexes, it also boast one of the largest and most beautiful cavern dives. Dos Ojos, which means "Two Eyes" in Spanish, is located just south of the X'el Ha ecopark. As you drive the bumpy dirt road back from the entrance, bear in mind that the original explorers of this system had to make this trip on foot, with their equipment hung on the back of burros.
The name Dos Ojos refers to two adjacent cenotes. Divers
usually enter from the smaller of the two, known as the Eastern Eye.
Two distinctly different types of cave dives are possible from this
As you head into the cave, there are actually several different lines you can choose. These lines seem to change frequently -- yet another reason why it is a good idea to use a guide for at least your first trip. One line will take you to the upstream portion of the cave, where you will see wide passageways and lots of formations. Yet another line will take you to Cenote Tak Be Ha, a huge, air-filled dome that can be artificially lit. This is a popular snorkeling site.
On your return, be sure to relax and enjoy the view
as you swim through the immense cavern. It is simply unequalled.
Sistema Dos Ojos is immediately adjacent to Sistema Nahoch Na Chich. For a while, teams of explorers were competing to establish which was the larger cave. There was also a considerable effort to make a connection between the two (to date, no one has succeeded).
So, which of the two is the world's largest underwater cave? Neither. It has now been established that Sistema Ox Bel Ha is much bigger than either Nahoch Na Chich or Dos Ojos. Unfortunately, it is a site that is not readily accessible by recreational cave.