Bacalar Chico is a park at the northern tip of the island. The trip we took a year or so ago started out in town, went thru the lagoon to the back side of the island, then north. You stop at the park site on the back side of the island, then go thru the "cut" or the part cut thru the mangroves (help me here if I'm wrong) by the Mayas. This part is about 10 feet wide, with Mexico on the left hand and Belize on the right. There is one snorkel stop soon after re-emerging to the Caribbean side, then lunch on the beach, then two more stops on the way south back to town. At one point you have to go outside the reef for a bit. At one stop we saw some amazing coral, including brain coral about the size of a VW. Also saw a lot of small sharks. The visibility is fantastic, and there are no other snorkelers anywhere near you except those on your boat.