Ten women and 82 men, who were rounded up during a Myanmar army sweep in a southern border region, were given the jail terms for violating the country's immigration and forestry acts, a local official said.
"They are still being interrogated at the court for cases relating to illegal drugs and weapons," he told AFP by telephone.
The fate of the detainees was discussed in talks between Thai Prime Minister Yingluck Shinawatra and Myanmar's President Thein Sein in Bangkok on Monday.
Thai government spokeswoman Sansanee Nakpong said the Myanmar leader pledged to help those imprisoned, but because of drug and arms charges, assistance would have to wait until after the cases had been tried.
Earlier this month, the state mouthpiece New Light of Myanmar detailed weapons seized -- including nine assault rifles, 11 "homemade" guns and a landmine -- but said no shots were fired during the raids in the country's southeastern Tanintharyi region.