Last year, around a million people turned out for the demonstration on Catalonia's national day, known as the “Diada”, which marks the fall of Barcelona to Spain in 1714.
The protest comes just weeks ahead of a crucial ruling by the Supreme Court in the trial of 12 separatist leaders who led the failed 2017 bid for independence, triggering Spain's worst political crisis in decades.
But two years on from the failed independence push, the separatist movement remains sharply divided, and Wednesday's turnout was likely to disappoint organisers who had chartered hundreds of buses to bring in supporters.
Wearing turquoise T-shirts and waving striped red-and-yellow Catalan separatist flags, protesters gathered in Plaza Espana, among them families with young children and pensioners carrying camping chairs.
In a nod to the anniversary, the rally began at exactly 1714 (1514 GMT).
The rally comes at a critical time for the separatist movement ahead of the Supreme Court ruling in October.
Nine of the separatist leaders face the most serious charge of rebellion, including former Catalan vice president Oriol Junqueras, for whom prosecutors have sought a 25-year jail term.
If they are convicted, Catalans must flood the streets in protest, insisted 55-year-old teacher Lourdes Vilardaga, telling AFP she hoped the region's leaders would be “up to the task”.
“Maybe we thought independence would be a switch that you turn on and that's it. Now we see it's a long-distance race, more difficult, but there is no turning back.”
On October 1, 2017 the regional government of Catalonia, which accounts for about one fifth of Spain's economic output and is home to some 7.5 million people, pushed ahead with a banned independence referendum.
But the vote was marred by police violence, and although the separatists made a declaration of independence, it was short-lived.Today, many senior separatist leaders not behind bars have fled the country, including former Catalan president Carles Puigdemont who is now based in Belgium.
The two main separatist parties that govern Catalonia have been unable to agree on how to continue pushing for independence.
Catalan president Quim Torra's Together for Catalonia party has called for “confrontation” with Madrid while Junqueras' leftist party ERC has called for dialogue with Spain's central government, which is less hostile to the separatists since Sanchez's Socialists came to power in June 2018.
“We will once again exercise any right which we are denied, including that of self-determination,” Torra told reporters on Wednesday at the rally.
– 'Competing amongst themselves' –
Ruben Saez, a 20-year-old illustration student with a Catalan separatist flag draped across his back, said people were “fed up” with the in-fighting which was “causing a lot of damage” to the movement.
“Instead of fighting for a common goal, the parties are competing amongst themselves,” he added.
The most recent Catalan government opinion poll showed 48.3 percent of those surveyed opposed independence while 44 percent were in favour.
The Catalan national day has always been widely observed, but since 2012 Catalan separatists have used the occasion to hold massive rallies that have drawn up to a million people.
Many who favour staying with Spain shun the event.
Prime Minister Pedro Sanchez told parliament on Wednesday he hoped the Diada would become “the festival for all Catalans and not just a part of them”.