Washington CNN  — 

Americans looking to sail between the United States and Cuba will soon be able to board ferries destined for the island, though restrictions on who can operate the service and what types of travelers they carry remain in place.

The ferry licenses were issued by the U.S. Treasury Department’s Office of Foreign Asset Control, according to an agency official, who couldn’t specify the number of licenses that were issued or the names of the carriers who received them.

However, at least two Florida-based lines – United Caribbean Lines and Airline Brokers Co. – confirmed they had received licenses to operate ferry routes between ports in Florida and Cuba. A Puerto Rico-based carrier, America Cruise Ferries, also confirmed they had received a Treasury license for ferry operation on Tuesday.

RELATED: Obama plans post-presidency agenda

The lifting of a ban on ferries between the neighboring countries – in place for decades – comes as President Barack Obama works to thaw relations with Havana. He met with Cuban leader Raul Castro in April, marking the first time a U.S. president has met his Cuban counterpart for substantive talks in more than half-a-century.

Obama has also worked to lift long-standing restrictions on travel to Cuba. Cuban-Americans visiting family, officials on government trip, and journalists no longer need to receive special permission before traveling to the island, though tourist travel is still prohibited.

The Treasury official said Tuesday the agency was issuing specific ferry licenses on a “case-by-case” basis, and not allowing blanket permission for ferry services to the island.

Advocates for ferry service between the U.S. and Cuba – which at their closest points are separated by only 90 miles of sea – say boat transport is more cost-effective than air charters, which can cost hundreds of dollars per passenger.

“This is a significant opportunity to advance U.S.-Cuba relations,” said James D. Whisenand, an attorney for America Cruise Ferries, calling the newly issued licenses “a significant green light of the new U.S.-Cuba relationship and a major proponent of the people-to-people policy endorsed by the Obama administration.”

“The new ferry service will allow people to board their cars in Miami and arrive in Havana within 9 hours,” Whisenand said.