Yes, it is recommended to exchange money in Isla Mujeres, Mexico. The official currency is the Mexican peso, and although some stores accept U.S. dollars, the peso is generally preferable and can result in better prices for goods and services. There are several places on the island where you can exchange money, including banks, exchange offices and automated teller machines (ATMs). It is advisable to check the current exchange rate before exchanging to ensure you are getting a fair deal.