The movement, known locally as "Hirak", first mobilized in February 2019 and within weeks forced then president Abdelaziz Bouteflika to abandon a bid for a fifth term and resign.
It called a halt to protests early last year as coronavirus restrictions took hold, but returned to the streets late last month to celebrate its second anniversary, protesting every Friday since.
"Hirak rallies will continue until this regime, which refuses to hear our voice, ceases to exist," said Bilal, a 37-year-old civil servant who joined the protest in Algiers.
Several marches converged in the early afternoon in the capital, following Friday prayers and amid a heavy police presence, while a helicopter hovered overhead.
"I hope that my children and grandchildren get to live in a better Algeria than the one I have lived through," said Khadidja, a protester in her seventies.
She said she had taken part in every rally since the first one on February 22, 2019.
Journalist Khaled Drareni, recently freed after nearly a year in custody, covered Friday's protests on his social media accounts.
Protesters lashed out at the intelligence services, accusing them of being "terrorists." Detainees said they were tortured in custody.
Protesters see the regime as little changed from the one led by Bouteflika.
Current President Abdelmadjid Tebboune, once a prime minister under Bouteflika and elected in a widely boycotted December 2019 presidential poll, has ostensibly reached out to the protest movement while seeking to neutralize it.