Civic groups and students led small-scale protests against military rule on the coup's one-year anniversary on Friday.
A dozen members of the Young People for Social-Democracy Movement staged the first anti-coup demonstration of the day at the October 14 Memorial on Ratchadamnoen Avenue, but were soon rounded up and taken to Chana Songkhram police station.
No serious charges were filed.
Later on, seven members of the Dao Din group — which entered the spotlight after holding an anti-coup stunt in front of Prime Minister Prayut Chan-o-cha in Khon Kaen last year — held a banner protesting against the coup in front of Khon Kaen's Democracy Monument.
The group and six other student colleagues were rounded up by soldiers before being taken to the provincial police station.
The group was urged by police to confess to breaking the NCPO's order banning political gatherings, but they did not, a student source said.
In Bangkok, the Resistance Citizen group's plan to conduct a walking protest from the MRT station on Lat Phrao Road to the Criminal Court on nearby Ratchadaphisek Road to file a charge against the coup makers was foiled.
Scuffles broke out after police attempted to arrest core members of the group, but they were eventually taken to court.
The group managed to file a lawsuit against the five leaders — including Gen Prayut — who staged the coup on May 22, 2014.
Immediately after filing the lawsuit at the court, police took them back to Phahon Yothin police station.
Arnon Numpa, 30, a lawyer from the Human Rights Lawyer Centre, and one of the core members of the Resistance Citizen group, said the lawsuit was filed by 15 people, with the aim of punishing the coup-makers.
The 20-page lawsuit cited Penal Code Article 113, which deals with acts of violence or threats to commit an act of violence in order to overthrow or change the constitution, the legislative, the executive and the judicial powers.
The court will declare how it will deal with the lawsuit on Friday.
In the evening, a group of university students from Kasetsart University held a silent protest against the coup at the Bangkok Art and Cultural Centre. Several were arrested after police intervened.