Transport Co reports more than 509,016 people left Bangkok on 27,558 inter-provincial buses and vans from Christmas Day to Saturday.
Jirasak Yaovatsakul, president of the state enterprise, said on Sunday that Transport Co deployed its own buses and concessionaires' buses and vans to serve the travellers.
"Many people left for their native provinces on previous long holidays, so New Year traffic will not be as congested as last year," Mr Jirasak said.
On Saturday alone, 159,713 people left the capital on buses and vans. The traffic was les congested than earlier expected, he said.
He assured that there were enough buses and vans and no passengers were left stranded at terminals.
At the Mor Chit bus terminal on Saturday, many people took short trips from Bangkok to Nakhon Ratchasima province, Mr Jirasak said.