Seventeen Myanmar nationals, one a child, were arrested for illegal entry late on Sunday night on the bank of the Moei River in Mae Sot district by a patrol of the 4th Infantry Regiment.
They were all soaked after crossing the river by boat and landing on the Thai side in pouring rain.
There were 12 men, four women and one child. They had no travel documents. All passed an initial health check .
They admitted they had crossed the river, which marks the border, and illegally entered Thailand to look for work, police said.
They were handed over to Mae Sot immigration office for legal proceedings.