At 9am, Mr Suthep and PDRC co-leaders performed a merit-making ceremony at the King Rama VI Monument, located at the gate to Lumpini Park, before leading the procession.
The Erawan Emergency Centre of the Bangkok Metropolitan Administration (BMA) had prepared more than 40 medical teams to look after people who joined the PDRC-led march.
On Friday, former Democrat Party power broker Suthep said the march "aims to make our intention known that we want immediate national reform, not [a rushed] election. We want to say this; 'Don't hold the election [too soon]. Masses of people [will] definitely boycott it."
Fifty-three political parties, with the notable exception of the main opposition Democrat Party, on Friday called for a fresh election to be held as early as May to break the country's political deadlock.
The party leaders and representatives have called on the Election Commission (EC) to meet with the caretaker government next week to discuss new poll preparations.