The official currency of Cuba is the Cuban peso (CUP).
This is the only legal currency allowed in Cuba. However, more established tourist centers, such as private hotels, bars, and restaurants, accept payments in US dollars, euros, Canadian dollars, and British pounds. The euro is the most widely accepted currency on the island outside the Cuban peso.
In the past, Cuba was known for having a dual currency system that separated the Cuban peso from the tourist monetary unit known as the Cuban Convertible Peso. As of January 2021, Cuba united its dual system into a single currency.
When traveling from the United States, most credit cards or debit cards will not work on the island. You should bring enough cash to cover meals, tours, accommodations, and other purchases not pre-paid before your trip. Cash tender is also the best way to make purchases in rural towns, villages, or directly from artists and cigar vendors.