Con3Post  research  highlights  severe  challenges  related  to  the  posting  of  third-country  nationals (TCNs). This  policy  brief  is  based  on  a  regional  report  of the  Con3Post  project1and  focuses  on the posting  of  Ukrainian  workers  through  Poland  to  work  in  the  construction  sectors  of  Estonia  and Finland. Most importantly, our study finds that TCN posted workers  have  multiple  vulnerabilities to exploitation  and  abuse,  when  compared  with  intra-European  Union  (EU)posted  workers.