A group of die-hard campaigners called 'Resistant Citizen', who have repeatedly defied the junta's ban on political protests, were prevented from marching to a court in Bangkok to file treason charges against junta chief Prayut Chan-O-Cha.
At least four of the group were arrested, an AFP photographer said.
Meanwhile seven students were wrestled to the ground and detained for holding an anti-coup banner in the northeastern city of Khon Kaen, a bastion of support for Yingluck Shinawatra whose government was toppled by the May 22, 2014 coup.
But widespread dissent appeared unlikely with the country still in lockdown.
Thailand's military took over last May after months of violent protests by anti-government supporters paralysed the elected administration of Yingluck Shinawatra.
She was dumped out of office by a court ruling two weeks before the coup. Martial law was imposed two days before the coup by the military.
In the past year, protests have been smothered, dissenters arrested and anti-coup radio and television stations shut, while royal defamation cases have surged as rights groups say the space to speak freely diminishes.
The junta says its power grab restored order after months of protests against Yingluck left dozens dead and the economy in a straitjacket.
"I did it (the coup) myself because I thought that both the country and the people were in severe danger... I made up my mind alone," former army chief-turned prime minister Prayut Chan-O-Cha told reporters today.
The junta says it is rebooting the kingdom's economy -- although economic growth last year was just 0.7 per cent, the weakest in three years.
