Prominent pro-democracy activist Panusaya “Rung” Sithijirawattanakul led the peaceful demonstration from 10am.
Activists also placed messages of support for the lese majeste detainees on the prison's gate and sign.
Among the 10 protesters being held in the jail are Parit “Penguin” Chiwarak, Arnon Nampa, Somyot Phurksakasemsuk and Patiwat "Mor Lam Bank" Saraiyaem. Dozens of pro-democracy protesters have been charged with lese majeste since October last year.