This article examines factors that could contribute to explaining variation in take-up of leave among fathers in the light of the EU’s Work–Life Balance Directive (WLBD). The WLBD seeks to equalize care responsibilities between fathers and mothers, especially through reserved leave, with high compensation. The article begins with a cross-country overview of take-up of leave among eligible fathers, considering earmarking and the degree of compensation. Our results show variation, which cannot fully be explained by policy design (presence of high compensation with reserved leave for fathers). The article then theorizes that instrumental resources – information and accessible administrative application procedures – could be a missing link to understand the actual shift from de jure to de facto social rights. The article then carries out embedded case studies on these two aspects of instrumental resources, using original qualitative data collected during the implementation of the WLBD. The most striking finding is that countries with similar formal implementation of earmarked paid parental leave, display significant differences in commitment to instrumental resources. Put differently, the WLBD is being implemented differently, not regarding formal social rights, but on instrumental resources. This finding is important because it means that EU-initiated legislation on parental leave, could lead to differences in outcomes, that is, take-up of leave among fathers. The implication of our findings is that decision-makers and policy actors at EU level and in member states, should focus more on instrumental resources in the implementation process. This is particularly important for enhancing the de facto legitimacy of the EU in social policy, given that EU social regulation is increasing via the European Pillar of Social Rights.