I think here is a ferry that runs every half hour from Cancun to Isla Murejes for just a few dollars but have never figured out where to get on it..... anyone know where?
You can grab the ferry at Playa Tortuga, which also features plenty of free parking. Tickets are 150 pesos each. First ferry leaves at 9:30 AM, last return to Tortuga is usually 5:30 PM. They sail at 1 hour intervals. There is a hole in the schedule between 1:30 and 3:30. There is another ferry that departs Puerto Juarez, but I'm unfamiliar with the schedule.
There is one leaving the new port at Puerto Juarez, every half hour, or more depending on the clients waiting, it costs 35 pesos, take 15 minutes to get there. You take Bonampak to Lopez Portillo, turn right, then follow the street until you find it. You can't miss it, they are building a huge ugly parking lot in front of the tower.
But if you're in the Southern end of the ZH, Puerto Juarez is much further than Playa Tortuga. Either ferry arrives at and departs from the same terminal on the island.
But with 2 people at Tortugas at 150 mxp you could pay for the taxi to Puerto Juarez and get the ferry tix there for only 70 mxp round trip. You also get the scenic road trip through town!!
The port that Jenlieb is talking about is called Gran Puerto and a few hundred yards farther is the actual port of Puerto Juarez. GP is easy to spot as there is a really tall building, more like an observation tower, that is actually a restaurant. The minute you turn right from either Bonampak or Tulum you can see this building. Some, but not all, of the R-1 buses go to this area. Just make sure it say Pto Juarez on the front of the bus. You can also change buses from the R-1, getting off at McDonalds and from there catch the R-13, but why bother. The GP and the PJ boats are a lot faster than the PT boats and a better overall "experience". GP gets my vote. I am going there on Saturday and staying overnight on the island.