Have a look at our Yucatan map http://yucatantoday.com/en/maps/map-yucatan-peninsula and you will see that from Cancun you first have to get to Merida and then go on to Progreso. From Cancun airport you will take a cab or shuttle to the Cancun bus depot (about 30 min.). Then you will take the bus to Merida (about 4 hours). Then you will take a cab to the place where the buses go to Progreso (about 10 minutes). Then you will take a bus to Progreso (about an hour). Click here for all the details: http://yucatantoday.com/en/topics/yucatan-bus-lines-and-taxis Specifically, read the paragraph at the end "Arriving to Cancún and want to get to Mérida?" and the paragraph further up "To Progreso". Hope this helps. Happy travels!