Turnout for the protests in Barcelona was about 18,000, according to local media citing police sources - around 10 times less than during the anniversary last year.
Supporters of Catalan independence chanting "Freedom for the political prisoners" and "Independence!" took part of a peaceful rallies Tuesday that failed to draw massive crowds at a time when the restive Spanish region has come to a crossroads.
The protesters were commemorating the second anniversary of a banned independence referendum just ahead of the verdict, expected in the next two weeks, for 12 Catalan leaders on trial for their role in that ballot and the short-lived independence declaration that followed.
The referendum, held on Oct. 1, 2017 after being deemed illegal by Madrid, plunged Spain into its biggest political crisis in decades, which still dominates national politics.
"We want to continue the fight for a referendum," said one of the protesters in Barcelona, Dolors Riba with a Catalan flag on her back.
Protestors say their leaders on trial, nine of whom are jailed, are political prisoners. Spanish authorities affirmed they were getting a fair, non-political trial.
Spain's high court last week jailed seven Catalan activists, with prosecutors claiming they had made explosives and were planning violent action around the time of the verdict.
The regional parliament responded to the arrests by adopting a resolution backing civil disobedience, while leaders of the pro-independence movement insisted on Tuesday they are non-violent.
The seven activists arrested last week are alleged to be linked to the grassroots CDR, one of the organizers of some of Tuesday's protests.
"We were born to defend a referendum. We grew to defend a republic. We are the ones who will make the enemy tremble. And we will win. Have no doubts," the CDR said on Twitter.
The rallies were more peaceful than during the referendum's first anniversary, when the police clashed with protesters when they tried to storm parliament.
In 2017, Madrid responded to the declaration of independence by the region's parliament by imposing direct rule on the region for months, sidelining regional authorities.
Acting prime minister Pedro Sanchez threatened on Tuesday to again apply direct rule in Catalonia if the regional government broke any laws. The leaders said Madrid was trying to paint their movement as violent, a label they reject.
"We urge the Catalan independence movement not to play with fire, not to make the worst possible mistake, which is to look the other way if there are signs of violence, as we have unfortunately seen in recent weeks," Sanchez said in an interview with broadcaster Cadena Ser.
Laura Borras, a lawmaker for secessionist Junts per Catalunya, said in comments to Reuters that it was the Spanish government that had "set fire to Catalan society" with its actions.