The group was led by Syed Sulaiman Husaini, leader of the Shia Muslim branch in Thailand, who called for an immediate stop to "radical racism and genocide" in the Gaza Strip.
The rallyists raised banners calling for peace while representatives condemned the Israeli strikes and bombing of a Gaza hospital. Participants then stood in silence for a minute to mourn the deaths of war victims.
Israel and Palestinian militants have traded blame for the hospital strike late on Tuesday, with the Israeli army saying later that it had "evidence" to prove Hamas fighters were responsible.
The hospital strike came after the Israeli military began air strikes to retaliate a surprise attack by Hamas militants on the morning of October 7. The renewed conflict has left more than 3,000 people dead in Gaza and at least 1,400 killed in Israel, with several thousands more wounded.
Syed told reporters that Palestine supporters in Thailand will not use violence in their protest and would use only symbolic acts. He urged the media “not to cover their mouths” when they condemn the oppression that has happened for the past 75 years.
Sayed added that the Hamas group would not harm Thai workers who have been taken hostages and would release them as soon as possible because “everyone who is not an Israeli are Palestine’s guests”.
An Israeli flag was burned during the protest on Saturday amid close monitoring by Metropolitan police officers.
Political activists Jatuporn Prompan and Nititorn Lamlua, co-leaders of the Kana Lomruam Prachachon (Melting Pot Group), also participated in the protest.