Only 16 convicts have been jailed, however, as three others are on the run and were convicted in absentia.
The 19 suspects were arrested two months ago by Myanmar authorities at a hotel in Tachilek, opposite Chiang Rai's Mae Sai district, while gambling illegally at the hotel's casino, the source said.
The Tachilek court on Monday sentenced the Myanmar owner of the casino to one year and 9 months in prison while nine other Myanmar nationals who were found to have acted as dealers were each handed one-year sentences, said the source in the Thai-Myanmar border coordination committee.
The other nine are gamblers.
Among them are six Thais who were given six-month sentences, said the source.
However, three of the nine gamblers convicted — one Thai and two Myanmar nationals — have previously jumped bail and are still at large.
The 16 people were yesterday taken to Chiang Tung prison in Myanmar after their conviction.
The Myanmar authorities continued to look for the other three, who are believed to still be on Myanmar territory.