Fourteen children have already been handed over to immigration authorities for repatriation, after surviving the deadly trip across the Thai border in the airtight seafood container.
Two other survivors are being treated in hospital for dehydration and lack of oxygen.
The deaths shocked Thailand and sparked calls for tougher measures to protect the thousands of desperate people who come to the kingdom in search of jobs.
The court in the southern province of Ranong, where the migrants were abandoned on a roadside with the dead, gave them a two-month suspended sentence and a $31 fine for illegal entry.
Since they had no money, they were sentenced to three days in jail, a court official said.
Children separated
Dave Mathieson, a researcher with the Human Rights Watch, said the decision to separate the survivors from their children and then prosecute them was "depressingly standard".
"It certainly goes against the shock and outrage that you see around the world, that something like this can happen," he said.
Police are still hunting for Suchon Boonplong, 38, the driver of the lorry carrying the fatal container, which he left open on a roadside after discovering the deaths.
A $1,500 reward is on offer for information leading to his arrest.