This study aims at comparing legal practices in the execution of sentences within the framework of cross-border cooperation between The Netherlands, Belgium and Germany. Based on quantitative and qualitative data, the implementation of the EU Framework Decisions 2008/909/JHA on the transfer of prisoners and 2008/947/JHA on the mutual recognition of judgments and probation decisions in the three countries is analyzed. Interview data with legal practitioners suggest that social rehabilitation, consents of the convicted individuals and the actual place of living, play an important role in the initiations of transfers. Empirical evidence that both Framework Decisions are increasingly instrumentalized for migration control purposes, as the current scientific debate suggest, is weak in the three case countries. The relatively small numbers of transfers of prisoners and judgements show, that the transfer instrument is still not implemented to its full potential. This study exemplifies remaining challenges connected to the principle of mutual trust in the daily practice of cross-border legal cooperation within the EU.