The most common non Mexican national currency is the US Dollar. This is due to being the commonly used currency internationally and the bulk of tourist that come from the United States.
You will find most places accept US Dollars. But there is the rate at what they will accept them, and usually it is at a lower rate than what the exchange is. Most of the time their rate will be a couple of pesos less than the official rate is. For this reason we do recommend people exchange money and use Pesos. You will get the best prices and the best use of your money if you exchange it and use Pesos.
Anywhere in the Riviera Maya you are able to use US Dollars at most big grocery stores. This places will exchange them at a better rate than the exchange houses. There are exceptions though. You are limited to $250 Dollars at a time and you cannot get more than 10% back in change. The change is in Pesos.
There is a money exchange located in the Puerto Morelos Town Square. Exchange rate is posted above the window. Count your change. These folks are notorious for short-changing. There is another located in the CI Banco, CI Banco usually gives a better rate than the booth on the square.
If you are changing US Dollars, you need to show your passport. It’s not their policy, it is federal law. There is no place that will exchange or accept Traveler’s Checks.
There are no banks in the beach part of town, on the other side of the highway there is one called CI Banco located in the storefronts of the Chedraui grocery store, and one called Bancomer in the Super Aki Plaza.
There are several bank machines in Puerto Morelos which work with your foreign card and dispense pesos. For security, we recommend using only ATM machines inside a commerce, like in the Chedraui grocery store or in the 1st OXXO driving in to town. There is also some at the CI Banco, or the machines at the Chedraui grocery store on the Colonia side of town.