The growth of immigrant labour in Central and Eastern Europe (CEE) has put pressure on labour market institutions and actors shaping industrial relations. Estonia, Slovakia and Slovenia – countries representing different models of capitalism – have adopted different regulatory strategies to address the growing need for temporary migrant labour. In some sectors, the high presence of migrant workers on temporary contracts puts pressure on wages and working conditions, creating conditions for sectoral and company-based migrant labour regimes (MLR). Starting with the thesis on the divergence of industrial relations in the EU's eastern periphery, we investigate the roles of employers and trade unions in Estonia, Slovakia, and Slovenia in addressing the issues arising from the temporary employment of migrant workers. While there are convergences towards similar outcomes, there are also clear differences: from the near-absence of trade union action to help migrant workers to new forms of employee representation. In all three countries, the driving force behind the increased reliance on migrant labour has been some employers’ economic need to fill low-paid jobs. Our article shows that trade unions and employer organisations are involved to varying degrees in the national regulatory processes concerning changes to the labour market access of TCNs. However, their influence on sectoral or company-level migrant worker employment practices is low to non-existent. While these sector- and company-based MLRs are growing in significance, trade unions in particular are caught in a vicious cycle of deregulation and reregulation.