Democracy protests demonstrated in the streets of Bangkok on Saturday as a rally expected to draw tens of thousands of people who started asking Prime Minister Prayut Chan-O-Cha to resign and demand reforms of the monarchy.
The kingdom has seen almost daily rallies of youth-led groups since mid-July, calling for the resignation of Prayut, the former army commander behind the coup in 2014, and a complete overhaul of his administration.
Some also demand reforms of Thailand's ultra prosperous and powerful monarchy – a topic such as a was once taboo in Thailand because of its harsh royal defamation laws.
The burgeoning movement, partly inspired by Hong Kong's pro-democracy protests, remains largely leaderless.
But this weekend's demonstration is organized by students from the Bangkok Thammas at the university – a group that has been among the loudest about the role of the royal family in Thailand.
At noon, a crowd of hundreds forced to open the campus' locked gates, singing "Down with dictatorship, long live democracy!" and "Prayut get you out!"
"We must support the students," Rianchai, 55, told AFP.
"We just want equality."
Prominent student activist Panusaya Sithijirawattanakul said on Friday Reforming the monarchy was at the top of the agenda, claiming that they hoped "to adapt it to our society".
Wearing ponchos, face masks and carrying umbrellas to shield themselves from the rain, protesters held up the thimble thesis, made popular by the Hunger Games film trilogy.
Protesters are expected to proceed to the historic Sanam Luang field in front of the Royal Palace, where they plan to spend the night before marching to the Government House on Sunday – a move the authorities have warned against .
The power show is expected to be the largest since the coup in 2014 – student activists hope for more than 50,000 turnout.
Around 10,000 uniformed and plain clothes police patrolled the area as the audience grew and set up tents selling t-shirts, flags and beer along a main road outside the university.
A cycle of violent protests and coups have long plagued Thailand, with the arch-royalist military embarking on more than a dozen putts since the end of royal absolutism in 1932.
The last wave of student-led demonstrations has been largely peaceful.
But unique calls from some protesters for honest discussions about the monarchy have sent shock waves through the empire.
King Maha Vajiralongkorn sits at the top of Thai power, backed by the kingdom's military and billionaire clans, and commands a fortune estimated at up to $ 60 billion.  Student demands include larger accounts of the palace's finances, the abolition of royal libel laws, and an invitation to the king to remain out of politics.
They also want a rewrite of the military-scripted constitution of 2017, which they say tipped last year's election in Prayut's favor, and that the government should stop "harassing" political opponents.
So far, the authorities have arrested more than two dozen activists, accused them of incitement before releasing them on bail.
Weekend demonstrations will prove a test for the pro-democracy movement, analysts say.
19. September is also the 14th anniversary of a coup that ousted then-Prime Minister Thaksin Shinawatra – which the self-proclaimed billionaire used as an opportunity to weigh in on Thailand's current state.
"Children see no future … as Thailand is now obsolete," Thaksin said in a statement issued Saturday, which did not explicitly express support for
"against the protesters" because they are children ".
The top-trending hashtag on Thai Twitter on Saturday was "September 19, we take back the power of the people".
Protesters gathered in front of Tokyo's famous Shibuya station on Saturday in solidarity with the Bangkok protesters, with further rallies planned in a dozen countries, including the United States and Germany.