Two orangutans were sent back to Indonesia on Thursday, three years after they were smuggled into Thailand.
Prakit Wongsriwattanakul deputy director-general of the Department of National Parks, Wildlife and Plant Conservation, passed the two female orangutans, both aged 4 years, over to Indonesian charge d'affaires Dicky Komar.
The handover marked 70 years of bilateral ties between Thailand and Indonesia, the DNP announcement said.
The primates, Ung Ing and Nathalie, were seized as they were being smuggled into Thailand through the customs checkpoint in Padang Besar of Songkhla province on June 21, 2017.
After the wildlife smuggling case ended, the DNP agreed to return the two apes to their home country, Indonesia.
Mr Prakit said it was the fifth time since 2006 that Thailand had returned seized orangutans to Indonesia, as part of a collaborative effort to combat the illegal trade in wildlife.
The four-year-old orangutans were transported from Khao Prathapchang wildlife sanctuary in Ratchaburi province to Suvarnabhumi airport on Thursday. They were to return to Indonesia aboard Garuda flight GA867, departing at 4.10pm.