The organisers said 230,000 turned up for the protest against a bill that seeks to allow extradition to mainland China, while police put the number at 56,000, the outlet reported.
The organisers reportedly said they wanted to inform tourists from other parts of China about why the legislation mattered. They promised to ensure the rally was peaceful to make a good impression.
Protesters wearing black shirts gathered in the afternoon outside the West Kowloon rail station, which links the semi-autonomous city to mainland China, before spilling into the Tsim Sha Tsui district.
They carried flags and banners and shouted slogans in the standard Chinese that is more common on the mainland. They called for the release of protesters detained during the June 12 rally, described by the authorities as unrest.