This paper explores the varying degrees of progress towards climate change adaptation action along trans-boundary river basins with the help of regime effectiveness theory. The authors use the activity diagram of the Management and Transition Framework for a comparative analysis of the Orange-Senqu river basin in Southern Africa, and Mekong river basin in South East Asia. The paper examines how effective river basin commissions and other elements of trans-boundary regimes interact to form climate change adaptation policy.The paper concludes that factors constituting high effectiveness of governance regimes in trans-boundary river basins are also likely to foster the development of climate change adaptation strategies. These regime effectiveness variables are characteristics of rules and procedures, organisational structures, and approaches of individual riparian countries in the international context. The authors point to the need for an analysis of additional factors that potentially shape decision-making and policy processes for climate change adaptation in international river basins such as:

the hydrological, political and socio-economic setting
underlying principles of regional cooperation (or conflict)
interests and values of the various actors in the negotiation process
the possible linkages and trade-offs with other policy fields.