Hundreds of demonstrators marched through the UK capital near Oxford Street chanting “freedom”, with some carrying placards stating “stop controlling us”, “ditch the facemasks” and “no more lockdowns”.
The Metropolitan Police said the arrests were for several suspected offences, including breaching coronavirus restrictions.
“We continue to urge people to go home,” the force said.
There was violence between demonstrators and the police. Some people fired flares and traffic was temporarily blocked on Regent Street as police made their arrests. Others were led away in handcuffs in Hyde Park.
The Met said three people were arrested at King’s Cross station in London before the protests on suspicion of breaching coronavirus restrictions.
There have been several anti-lockdown protests in central London since the onset of the pandemic.
The UK is in a nationwide lockdown until December 2 to try to flatten the curve of its second wave of infections. Protests and other mass gatherings are currently banned.
From Wednesday, the country will move into a tiered system, with areas with high rates ordered to follow stricter socially distancing restrictions.
Covid-19 has claimed the lives of at least 58,000 people in the UK and infected more than 1.6 million of them.
Officials also revealed at the weekend that up to 2.7 million people at risk of Covid-19 in England will be offered a free supply of vitamin D by the government.
Studies have shown that the vitamin helps strengthen the immune response against the virus. From January, care homes in England will automatically receive free supplies of the supplement for residents.