For decades, Cuban and U.S. diplomats have faced strict limits on their travel within the Cold War enemy countries.
Cuban diplomats at the United Nations in New York cannot go 25 miles beyond Columbus Circle in Manhattan or past the Beltway loop circling Washington without the permission of the U.S. State Department.
U.S. Interests Section workers, meanwhile, must submit detailed itineraries to Cuban officials if they want to travel outside Havana.
Recently, however, Cuban and U.S. diplomats have been increasingly, and more easily, stepping outside the once nearly insurmountable fences.
On the island, U.S. officials privately say they've had an easier time obtaining permission to travel outside the allowed perimeter.
And last week, two consuls from the Cuban Interests Section in Washington made a discreet visit to Miami. There they met with U.S. companies that offer charter flights to the island and small groups of Cuban exiles to talk about the easing of regulations allowing Cubans to travel and other reforms.
Earlier this year, the chief of the Cuban Interests Section delivered the keynote address at a University of Georgia law school conference on the economic embargo against Cuba. Two other Cuban officials went to Tampa in March to attend an event promoting engagement between the U.S. and Cuba.
"In the past, they have not had much luck," said Wayne Smith, a former chief of the U.S. Interests Section in Havana, and one of the hosts of the Tampa conference, titled, "Rapprochement with Cuba: Good for Tampa, Good for Florida, Good for America."
"The State Department usually said no," Smith said. "But in this case, it was, 'Yes.' And I would say a somewhat different tone. A more positive one."
The travel is part of a larger, slow-moving thaw between the two countries and comes as both prepare for a sit-down talk on migration issues on Wednesday. Cuba and the U.S. held talks last month on resuming direct mail service. A U.S. federal judge allowed a Cuban intelligence agent to return to the island in May. And Cuba recently decided to let an American doctor examine jailed U.S. government subcontractor Alan Gross.
Robert Pastor, director of the Center for North American Studies at American University, described the moves as "cautious steps."
"If the overall purpose is to find out whether the Cubans are interested in a serious relationship, I think we'll soon find the answer is yes," he said. "And then it will be better to proceed to some larger issues as well."
The U.S. and Cuba do not have embassies in each other's countries; diplomatic relations between the Soviet-era foes deteriorated after the 1959 communist revolution. But since 1977, both countries have operated Interests Sections under the legal protection of the Swiss embassies.
In the thick of the Cold War, both countries put restrictions on how far diplomats could move outside their respective capitals.
"I think there was a fear of espionage, so therefore, you want to keep your diplomats from traveling so widely that it's hard to follow what they may be up to," Pastor said.
Whether that concern exists now depends on who you ask.
"They are not a military rival to the U.S.," Pastor said. "They are not about to spring a surprise attack on the United States. There's no real military reason for them to do the spying."
Cuban-American Republican U.S. Rep. Ileana Ros-Lehtinen of Florida said the threat remains.
"While a U.S. citizen languishes in a Castro jail on trumped-up charges, the tyranny's spies are allowed to visit Miami to further advance their espionage activities," she said.
The island is still on the U.S. list of state sponsors of terrorism. In 2001, five Cuban intelligence agents were convicted of spying on exile groups, politicians and U.S. military installations in South Florida. Four of those men remain in U.S. prisons.
Havana denies any links to terrorism and contends its inclusion on the list is a political vendetta. In Cuba, the spies are celebrated as heroes.
The State Department was aware of the Cuban diplomats' travel to Miami, according to a State Department official who spoke on condition of anonymity because he wasn't authorized to discuss the matter publicly. The department declined to provide any further details.
A telephone at the Cuban Interests Section in Washington rang busy. Cuban government officials often don't respond immediately to requests for comment from foreign journalists.
Those who met with the diplomats said their visit was focused on practical matters such as passport renewals. Tessie Aral, the president of ABC Charters, said she was part of a meeting that brought together travel agencies that offer trips to Cuba.
"It's always helpful to meet with officials of either government that can explain to us how we can better help our customers," Aral said.