The military regime has kept a tight rein on dissent since its 2014 power grab by outlawing gatherings of more than five people and pursuing activists in the courts.
But impatience with the generals has been mounting ever since their latest delay of elections, which are now tentatively set for February 2019.
In one of the largest showings in a recent string of protests, around 500 people turned up for a festive picnic-style rally held on a university field in Bangkok on Saturday.
"Who out there has a fire for democracy?" one young activist called out to the crowd from the top of a truck, eliciting loud cheers.
While organisers raged against the military dictatorship over loudspeakers, vendors handed out free meals and sold shirts with sly references to a spate of graft scandals that have helped fuel the dissent.
One shirt bore the face of a black leopard, an animal that has become a symbol of inequality and corruption ever since a construction tycoon was caught hunting the wild cat in a wildlife sanctuary in February.
In reference to another high-profile scandal, veteran activist Ekachai Hongkangwan showed up in a vest covered with paper watches -- a jab at the junta no. 2, who is facing a graft probe after online sleuths spotted him wearing dozens of undeclared luxury timepieces.
In a nod to junta chief Prayut Chan-O-Cha's repeated poll postponements, another demonstrator donned a mask resembling the general's face and the character Pinocchio -- whose nose grows longer with each lie.
"This year more people are daring to (come out), especially after the junta government has failed to keep (its) promises on elections," Ekachai, who helped lead the event, told AFP.
Even if a vote is held next year, it will not restore the same level of democracy Thailand enjoyed before the coup.
A new military-drafted charter has turned the upper house into an appointed body and also opens a channel for an unelected premier to take office -- a set-up analysts say junta chief Prayut is eyeing.
(This story has not been edited by NDTV staff and is auto-generated from a syndicated feed.)