Mr Seri was freed on the condition that he stays in the country and does not incite unrest.
The release came after Dr Seri's lawyer applied for bail by posting a Bt600,000 savings account as bond in the afternoon.
Earlier, immigration police late morning detained Dr Seri, a well-known mass communication academic, on insurrection and seven other charges, at the country’s main international airport on his return from the United States .
Then, Dr Seri was taken to Ratchada Criminal Court by Department of Special Investigation (DSI) officers to acknowledge the indictments and proceed with prosecution.
He is one of 30 PDRC figures having arrest warrants on eight charges, including the insurrection charge.
The anti-government co-leader said that he travelled to the US to attend his nephew’s wedding on May 8, before the criminal court approved the warrants for him and 29 other protest leaders.
He said he did not flee and planned to turn himself in to police after returning to the Kingdom in order to prove his innocence.
Meanwhile, national police chief Pol Gen Adul Saengsingkaew, as advisor to the Peace and Order Maintaining Command (POMC), said that he was ready to comply with the POMC proposal by calling for DSI chief Tarit Pengdit to delay the request seeking warrants for more PDRC leaders in order to avoid possible problems.
Regarding arrest warrants previously issued by the court, Gen Adul said that police can continue the legal process as the statute of limitations is 20 years.
It depends whether or not the court will approve revoking the warrants, the national police chief explained.