Boca Paila
 
The most important Landmark of the Sian Ka'an Biosphere. Located 15 minutes south of the entrance arch. It is a Boca (ocean inlet) that joins the Chunyaxché Lagoon and the Mexican Caribbean Sea.

It is the site of an old fishing lodge specialized in light tackle fly fishing (tarpon, bonefish and permit). The bridge that passes over the Boca is the only roadway through Sian Ka'an and it ends at Punta Allen fishing village.