AT&T, the number-two wireless carrier in America, said it had signed a deal with Cuba's state-owned telecoms provider to offer direct roaming services to its customers visiting Cuba.
AT&T said on Monday it would announce the pricing and the launch date for the service at a later date.
Reuters reported in March that AT&T was trying to complete a mobile communications agreement with Cuba's telecoms monopoly, Empresa De Telecomunicaciones De Cuba (Etecsa).
The deal follows similar agreements between Etecsa and U.S. telecoms carriers including Sprint, Verizon, and T-Mobile after President Barack Obama's administration eased some sanctions on Cuba.
Earlier, phone calls between the United States and Cuba had to be routed mostly through other countries, adding to costs and reducing the quality of calls.