The King and his Camilla's coronation was celebrated in Scotland
Scores of protesters were gathered ahead of King Charles' thanksgiving service in Edinburgh.
BBC reported that the protesters chanted "not my king" as Charles cavalcade passed on the way to St Giles' Cathedral.
Another anti-monarchy group hosted a rally outside Holyrood, which was attended by Greens co-leaders Patrick Harvie and Lorna Slater.
Police Scotland said it had liaised with groups to ensure public safety.
"This pointless vanity parade in Edinburgh will cost Scottish taxpayers millions of pounds, and for what? So Charles can once again be centre of attention for a day," said Graham Smith, the chief executive of anti-monarchist group Republic who was arrested at the coronation in May.
Scotland is marking the coronation of King Charles with a grand procession, a fly-past and a service of thanksgiving
The couple was crowned in London's Westminster Abbey in May in Britain's biggest ceremonial event for seven decades.
Charles succeeded his mother as king of the United Kingdom and 14 other realms when Queen Elizabeth died in September.
But in a nod to the historical fact that England and Scotland had different monarchs until the crowns were united in 1603, there will be separate Scottish celebrations to mark his coronation on Wednesday.
A People's Procession, involving about 100 people representing various aspects of Scottish life, and a Royal Procession, featuring hundreds of service personnel, will be held along the Royal Mile in Edinburgh.
At a thanksgiving service in the city's St Giles' Cathedral, Charles will be presented with the Honours of Scotland - the Scottish crown jewels - including the new Elizabeth Sword, named after his mother and made to replace the one gifted to Scotland's James IV by Pope Julius in 1507 but now too fragile to use.
"The Honours of Scotland have immense historical significance, having been present at many major ceremonial events over the past 500 years," Scotland's First Minister Humza Yousaf said.
"Designed and crafted with care by some of Scotland's finest artisans, the Elizabeth Sword is a fitting tribute to the late queen as Scotland prepares to welcome the new king and queen."
The Stone of Destiny, the historic symbol of Scotland's monarchy and nationhood, will be moved to the cathedral for the service, for which the king has commissioned five new pieces of music.