According to the Spanish Government 1,300 of 2,315 schools have been closed as Spanish authorities stepped up their attempts to stop Sunday’s referendum.
The regional government’s telecommunications centre has also been occupied by police.
A referendum in the wealthiest region in Spain had expected to attract tens of thousands of voters.
Catalonia, which is home to 7.5 million people already has a high degree of autonomy and has its own language, but is not recognised as a separate nation.
Thousands of police have been sent to the region in an attempt to stop any vote taking place, with the Catalan police force, Mossos d’Esquadra, also stepping in.
Schools and other polling stations had been occupied by activists. Police confirmed that 163 of these were being “peacefully” occupied by people who would be allowed to leave, but no-one will be allowed in.
Officers have also been seizing items such as ballot papers, with websites linked to the vote also being closed by prosecutors.
Officials linked to the referendum have also been arrested.
Catalan leader Carles Puigdemont told Reuters news agency that the referendum would go ahead.
“Everything is prepared at the more than 2,000 voting points so they have ballot boxes and voting slips, and have everything people need to express their opinion,” he said.
On Friday, a final rally was held in Barcelona.
While there is no clear indication of what the outcome of a vote would be, the 2015 regional election was won by an alliance of pro-independence parties, with about 40% backing pro-Spain parties.
Protests in solidarity with Catalonia have been held across Scotland.