Cuba's best-known dissident, blogger Yoani Sanchez, checked in without incident at Havana's international airport on Sunday on her way to Brazil, the first stop on an 80-day-tour of a dozen countries.
She was sent off with hugs by a small group of family members and friends.
Sanchez was granted a passport two weeks ago under Cuba's sweeping immigration reform that went into effect this year, after being denied permission to travel more than 20 times over the past five years.
"I made it through immigration, now I only need to board the plane and take off," said Sanchez, who has promised to tweet throughout her saga.
In another tweet to her followers as she waited to board her plane, she added: "To tell the truth, my knees haven't stopped trembling."
Sanchez is one of a number of high profile government opponents who have received a passport under the new regulations, but the first to actually take advantage of the measure.
A few lesser-known dissidents have been denied passports.
Sanchez criticized the new law for not simply granting all Cubans the right to travel, but told Reuters at the airport, "I plan to take full advantage of it and push it to the limit."
The old travel law was put in place in 1961 to slow the flight of Cubans after the island's 1959 revolution.
The new law scrapped the much-hated requirement of having to obtain an exit visa and loosened other restrictions that had discouraged Cubans from leaving and traveling.
It was one of the wide-ranging reforms President Raul Castro has enacted since he succeeded his older brother, Fidel Castro, in 2008.
There are still travel restrictions, mainly for national security reasons and for those with pending legal cases.
PRIZE MONEY FOR A FREE PRESS
Sanchez, who has won a number of international prizes for her blog but has been denied permission to travel to collect them, said she would now do so and planned to use part of the prize money to "found a free press in Cuba."
"I plan to visit various media and make contact to learn how a modern press runs," she said.
Sanchez, a 37-year-old Havana resident, has incurred the wrath of Cuba's government for constantly criticizing its communist system in her "Generation Y" blog, and using Twitter to denounce repression.
She is one of the world's best-known bloggers and has tens of thousands of followers abroad, but few in Cuba where the government severely restricts the Internet.
Her blog is named after the penchant of Cuban parents during the Cold War era of Soviet backing for the island of choosing names for their children starting with "Y" because of the many popular Russian names starting with that letter.
Sanchez, considered Cuba's pioneer in social networking, told Reuters earlier this week that she would visit the headquarters of Google, Twitter and Facebook, and travel to Brazil, Argentina, Peru, Mexico, the United States, Spain, Italy, Poland, the Czech Republic and other countries.
Cuba's leaders consider dissidents traitorous mercenaries in the employ of the United States and other enemies. Official bloggers regularly charge that Sanchez's international renown has been stage-managed by Western intelligence services.
But Sanchez is also a critic of U.S. policy toward her homeland. In a recent blog, she said the decades-old trade embargo had failed to stifle the Cuban government and was exploited by Havana as "a big bad wolf to blame for everything."
"The big news is not now, but in 80 days when she will return," Bert Hoffmann, a Cuba expert at the German Institute of Global and Area Studies in Hamburg, said.
"Many regime opponents have left Cuba for exile, but this is the first time a prominent dissident sets out on a high-profile world tour to then come back to the island."
Sanchez's travels and eventual return to Cuba are being carefully monitored by governments and human rights advocates as a test of Cuban authorities' commitment to free travel.
"She is gone, now let's see if the government lets her back in or forces her into exile," a European diplomat said.