The sentences given by the Abu Dhabi Federal Court of Appeal came in a case described by the UAE government as involving the Muslim Brotherhood, a pan-Islamic organisation declared a terrorist group by the Emirates.
Activists, however, decried the case as targeting dissidents, something that drew attention and protests at the United Nations COP28 climate talks held in Dubai in November.
The state-run WAM news agency reported the verdicts after human rights activists said the sentences had been handed down.
Five defendants received 15-year sentences while five others received 10-year sentences.
Another 24 defendants had their cases dismissed, WAM reported.
"These over-the-top long sentences make a mockery of justice and are another nail in the coffin for the UAE's nascent civil society," said Joey Shea, a researcher focusing on the UAE for Human Rights Watch.
"The UAE has dragged scores of its most dedicated human rights defenders and civil society members through a shamelessly unfair trial riddled with due process violations and torture allegations."
The Emirates Detainees Advocacy Centre, a group run by an Emirati who lives in exile in Istanbul, separately reported that sentences had been handed down.
Amnesty International also criticised the sentences, saying the defendants had "been held in prolonged solitary confinement, deprived of contact with their families and lawyers and subjected to sleep deprivation through continuous exposure to loud music".
Those tried also were "forbidden from receiving the most basic court documents," it said.
"The trial has been a shameless parody of justice and violated multiple fundamental principles of law, including the principle that you cannot try the same person twice for the same crime, and the principle that you cannot punish people retroactively under laws that didn't exist at the time of the alleged offence," said Devin Kenney, an Amnesty International researcher.
Kenney described some of those tried as "prisoners of conscience and well-known human rights defenders".
WAM did not identify those sentenced.
But among those who received life sentences is activist Nasser bin Ghaith, an academic held since August 2015 over his social media posts, Shea said.
He was among dozens of people sentenced following a wide-ranging crackdown in the UAE after the 2011 Arab Spring protests.
Those demonstrations lead to Islamists, including Brotherhood member Mohammed Morsi in Egypt, rising to power in several Middle Eastern countries.
The Gulf Arab states did not experience any popular overthrow of their governments and cracked down against demonstrators and those perceived to be dissenters.
The UAE, while socially liberal in many regards compared with its neighbours, has strict laws governing expression and bans political parties and labour unions.
That was seen at COP28, where there were none of the typical protests outside of the venue as activists worried about the country's vast network of surveillance cameras.
