They are led by PDRC secretary-general Suthep Thaugsuban and other leaders including Akanat Promphan and Chinaworn Boonyakiat.
According to PDRC's plan, starting at 9am the protesters are to march along Silom, Charoenkrung, Chan and Narathiwat Ratchanakharin, Soi Suanphlu and Sathorn roads before returning to Lumpini in the afternoon.
Security is tight to ensure the safety of the protesters.
At the same time, Thaworn Senneam will lead the protesters from Victory Monument to the Natural Resources and Environment Ministry.
Issara Somchai will also lead demonstrators to march to undisclosed destinations from the Lat Phrao rally site.