Yoani Sanchez, a Cuban blogger and fierce critic of the governments of Raul and Fidel Castro, embarked on a long-denied trip abroad Sunday.
According to Sanchez, she has been repeatedly refused an exit permit for years because of her high-profile opposition to the government.
In January, Cuba ended its unpopular policy of requiring citizens to obtain a letter of invitation and an exit permit before leaving the country.
Dissidents said the policy was used to punish them for their anti-government advocacy.
While other government critics have left the country under the new law, Sanchez is the highest-profile figure in the dissident community to test the easing of restrictions.
Flanked by international news media, Sanchez quickly checked in for her flight to Brazil on Sunday and passed through an immigration checkpoint at Havana's Jose Marti Airport.
"In transit in Panama," Sanchez tweeted on Sunday night during a layover on her way to Recife, Brazil, to attend a conference on freedom of expression. "Many impressions."
Sanchez said she planned an 80-day tour of some 10 countries, including Brazil, Mexico and the United States.
Much of the funding for her trip, Sanchez said, came from donors and from people offering her a place to stay for free.
Sanchez has more than 400,000 followers on Twitter, but with irregular access to the Internet in Cuba, she said had been forced to communicate with the public by sending cell phone text messages that are uploaded to the social messaging service.
She said beyond attending technology forums and enjoying easier access to high-speed Internet, she was looking forward to meeting some of the volunteers who translate her writings from Spanish to other languages.
MJ Porter, who helps translate Sanchez's blogs into English from her apartment in Seattle, told CNN last year she couldn't wait to meet the Cuban blogger.
"I am a big crier, so I will probably cry for about an hour," Porter said. "Then I will laugh and then cry some more. It's hard for me to imagine."
Sanchez said she was surprised to be able to travel, especially because some Cubans still face restrictions on leaving the country.
The government still prohibits the travel of some officials, sports stars and citizens whose travel abroad violates "public interest."
A handful of other dissidents have reported that they were informed by the government they would be barred from leaving the country.
Longtime dissident Gisela Delgado said she was told by officials that even though she has a valid passport, she is on the list of Cubans who aren't permitted to travel.
"The state decides who can leave and who can't," Delgado said. "For 54 years, it's been a way to manipulate us and divide us, the whole Cuban family."
As Sanchez made her way though Havana's airport Sunday, she said no one needed to worry about her staying permanently outside Cuba or if the government could prevent her from returning.
"It won't happen," Sanchez said. "And if it did, all that would change would (be) instead of returning legally through an airport, I would come back on a raft."