The Criminal Court on Thursday again rejected the bail requests of seven co-leaders of the Ratsadon group.
The protesters' lawyer Krissadang Nutcharas said the court stood by its previous decision to refuse bail, as well as a similar rejection by the Appeal Court.
The reasons for rejecting the requests had already been explained in those previous rejections, Mr Krissadang quoted the court as saying.
Earlier in the day, the defendants' supporters gathered outside the court and handed in a letter demanding the release of the seven.
They are Panupong Jadnok, Parit "Penguin" Chiwarak, Panusaya Sithijirawattanakul, Chaiamorn Wibulkaew, Arnon Nampa, Chukiat Saengwong and Parinya Cheewinkulpahtom.
Mr Parit is currently on a hunger strike to protest the court's decision to repeatedly reject his bail applications.
Former Future Forward leader Thanathorn Juangroongruangkit acknowledged the court's decision but pleaded for the seven to be granted bail.
He said Mr Parit had had nine bail applications turned down and been detained for 51 days prompting him to go on a hunger strike for 45 days.
Mr Thanathorn questioned whether justice was being administered to the activists, bearing in mind they had not yet been convicted of anything.
The Corrections Department has denied reports on social media that Mr Parit had "excreted blood and flesh", saying he was physically well.