The protesters were joined by factory workers due to be laid off and groups seeking to preserve access to universal healthcare, Think Spain reported. Monday.
The anti-demonstration law, which affects even peaceful protests, calls for fines of $41,000 to $823,000 for anyone staging the marches.
The protests, which drew thousands of supporters in each of the cities, also want the Spanish Parliament to reject a proposed law restricting abortions.
Workers from Coca-Cola plants to be closed in three cities joined the protests after negotiations between unions and management failed.
Company officials have said they will end 750 jobs and relocate 500 other staff members. Workers contend the relocations are "clandestine" layoffs because the workers to be relocated would find it difficult to move.