The measured rate of primary school completion in the East Asia and Pacific region has exceeded 100%, but aggregate statistics inadequately reflect the experience of migrants, who are harder to count than sedentary populations. For Thailand several studies have found enrolment rates among migrant children to be very low, but the sparse evidence amid differences in geography and industrial sector means this pattern may not be universal. The present article reports a study which focuses in more depth on a particular migrant community in order to show relevant dynamics with greater specificity and clarity. It finds a higher enrolment rate than in the previous studies of migrants in Thailand, but also shows how many such children fail to complete their primary education through being placed in classes lower than the normal grade for their age. In this community the benefits accrued from school enrolment were therefore limited compared with the costs, resulting in family separations as some children were left in the home country and some entered employment early. In the 15-17 year age range, girls rather than boys were separated from the parental home.