The King is thought to spend most of his time in Germany.
At 6pm, the protesters sang the national anthem while holding up the three-finger salute. The march started about half an hour later than initially scheduled from Sam Yan intersection and as of press time were only close to Chulalongkorn Hospital.
Their destination is the German embassy on Sathorn Road in the heart of Bangkok.
Most protestors began gathering at the intersection at around 4pm, though barriers were set up outside the Samyan MitrTown and Chamchuri Square complexes from around 3pm.