The Vietnamese fishing boats were arrested in mid-July, 2016, by the Thai coast guards. The captain and crew of the fishing boats went on trial for illegal fishing and labour abuse.
Other fishermen were kept temporarily in Songkla Province, for further investigation.
Nguyen Hai Ngoc, a representative from the Vietnam Embassy, said that since 2016, Thai coast guards have arrested 86 Vietnamese fishermen for illegally fishing on Thai waters.
The 27 fishermen are now in good health and are in contact with their families at home.
The Embassy has completed procedures to send them home next week.