Hundreds of thousands of protesters have taken to the streets on several occasions since mid-October over speculation that President Alpha Conde, 81, is seeking a third term.
At least 20 civilians have been killed in the unrest to date, plus one gendarme.
On October 22 a court in the capital Conakry jailed several protest leaders on charges of organising unauthorised demonstrations and paralysing the economy.
However, lawyers representing the activists persuaded a court on Thursday to free 10 of them pending an appeal trial due to start on December 5.
Cries of "freedom" from oppostion supporters rang out in the courtroom following the verdict, according to an AFP journalist who was present.
Abdourahamane Sanoh, the co-ordinator of the National Front for the Defence of the Constitution (FNDC), an alliance of opposition groups, was among those freed.
"We have won a battle but on December 5, we will win the war," said Saloum Assia Cisse, an FNDC activist.
The protest leaders' lawyers successfully argued to postpone the appeal trial by one week on Thursday in order to give them time to prepare their case.
They also convinced the court to the release the activists until that date.
"We have always said that this trial had no reason to exist," said Mohamed Traore, one of the lawyers.
"We are going to fight again so that the appeal judge knows that innocent people were found guilty in the first ruling," he added.
A former opposition figure himself, Conde became Guinea's first democratically elected president in 2010.
But critics say his regime has become increasingly authoritarian.
In September, he launched consultations on the constitution, which limits the number of presidential terms to two.
Conde has neither confirmed nor denied his intention to seek a third term.
Guinea, a former French colony, is rich in minerals but ranks among the poorest countries in the world. In the UN's 2018 Human Development Index, it was listed 175th out of 189 countries.