The combined effects of socio-economic growth as well as climate change exert increasing pressure on international river basins and require dedicated cooperative efforts to jointly manage international rivers. Cooperative strategies drawn from scientific literature, empirical research and practitioner’s handbooks are explored and clustered into six key dimensions of goals, instruments, structures, actors, leadership and resources to provide an assessment tool of actor strategies for both scientists and practitioners. The exploratory framework is applied to Dutch–German cooperation in the delta of the Rhine catchment, testing its conceptual validity and applicability in international river basin management as well as providing policy recommendations for the study area. The assessment framework can serve as an instrument to inventory, map and evaluate the importance of specific actor strategies and to facilitate dialogue and cross-border cooperation between riparian countries. Alternatively, the framework can be put to use, for example by downstream countries, to assess and coordinate their range of strategies on the national, regional and local level in order to engage and influence their counterparts.