The best way to get to Akumal is to fly into the Cancun International Airport.  From there you can either rent a car or take a taxi just an hour south to Akumal.  We recommend renting a car because there are so many great places to explore nearby (about $150 per week). 

To enter Mexico as a US citizen you will need either a passport or a drivers license and birth certificate. US dollars are accepted everywhere but you might want to exchange for some pesos upon arrival to get a better rate.