HAVANA -Cuba's parliament has picked Raúl Castro's right-hand man, Miguel Díaz-Canel, as the sole candidate to succeed him, ending the family's long rule.
Mr Castro took over as president from his ailing brother Fidel in 2006.
An improvement in relations with the US which began under Barack Obama has been partially reversed since Donald Trump entered the White House.
Mr Castro is expected to remain a powerful influence in the communist state even after he steps down.
The National Assembly has voted on the nomination but the result will not be announced until Thursday, when he is expected to formally pass the presidency to Mr Díaz-Canel.
However, he will stay on as head of the Communist Party until its next congress in 2021.
The next Cuban leader will inherit a country in economic stagnation and with a young population impatient for change, BBC Cuba correspondent Will Grant reports.
There is also the complex task of leading without the same revolutionary past embodied by Raúl and Fidel, who died in retirement aged 90 in November 2016.
An era will end in Communist-run Cuba on Thursday when President Raul Castro retires, likely handing over the reins to his right hand man Miguel Diaz-Canel, born the year after brothers Fidel and Raul led their 1959 leftist revolution.
However after nearly 60 years of Castro rule, the change is not expected to herald sweeping reforms to the island’s state-run economy and one-party system, one of the last in the world.
First Vice President Diaz-Canel, 57, is seen as a stalwart of the Communist Party, designated by the constitution as Cuba’s guiding political force, who has worked his way up the party’s ranks over three decades.
For many Cubans, struggling with economic hardships, the transition in leader is seen as merely symbolic.
“We always wish the symbolic would translate into real and concrete actions for our lives,” said Jose Jasan Nieves, 30, the editor of an alternative news outlet to the state-run media monopoly. “But this isn’t the case.”
Cubans hope the next government can resurrect one of the world’s last Soviet-style centrally planned economies that has failed to improve under limited market reforms by Castro.
Those domestic economic woes have been exacerbated over the last year by a decline in aid from ally Venezuela and a partial rollback of the U.S.-Cuban detente, dampening a tourism boom.
Analysts say it will be tricky for Diaz-Canel to get the party and government to deepen the reform process, given his predecessor struggled to do so despite his clout as one of the revolutionary leaders.
Cuba’s relationship with the United States, that has nosedived since Donald Trump was elected U.S. President, is another major challenge Diaz-Canel will inherit.
Washington has reduced staffing at its Havana embassy to its lowest level since the 1970s due to a spate of unexplained illnesses among its diplomats - a political move to justify unraveling the detente, critics say.
The U.S.-Cuba detente, under former U.S. President Barack Obama in 2014, was one of the highlights of Castro’s presidency and part of his broader opening of the island in order to preserve Cuban socialism beyond his “historic generation”.
Castro allowed Cubans to travel more freely and to own cellphones and property, while expanding internet access, albeit continuing to limit public dissent.
On the economic front, he encouraged the creation of small private businesses from hairdressers to restaurants while encouraging more foreign investment.
But he did not get around to implementing most of his planned reforms, including key ones such as the unification of Cuba’s dual currency system - that will fall now to Diaz-Canel.
For more than two decades, two currencies have legally circulated in Cuba at multiple exchange rates, distorting the economy. The peso is used to pay most wages and local goods, while the CUC is used in the tourism industry, foreign trade and upscale eateries and stores carrying imported goods.
“People are waiting for a solution to the monetary duality,” said Jose Luis Gomez, a waiter at a Havana restaurant. “There is no profitable economy in the world with two currencies.”