Cash is king in Roatan. And that can come in the form of U.S. dollars (USD) or our local currency called Lempiras (HNL), so no need to try to exchange money prior to arrival. However, your dollars need to be in mint condition - no tears, even minor rips, and no writing. So it is advised that you go to your local bank and request new bills.
All businesses on the island will accept both currencies and even allow for you to mix them for payment, but you will almost always receive your change in Lempiras.
Exchange rate can fluctuate between 24.6 to 24.8 HNL to $1USD. It's easiest to calculate in your mind if you just use 25HNL = $1 USD.
Many places will offer a discount when paying in cash, Sun Divers included. Other forms of payment widely accepted are Credit Card (Amex, Visa, Mastercard only), PayPal and Venmo