The Naga Foundation aims to implement durable re-greening interventions to increase local soil sustainability and regional water availability. When this is done on a large enough scale such landscape changes may also lead to positive regional climate impacts. Naga is developing a plan to re-green 15 large areas in Eastern Africa, creating a so-called hydrological corridor. Four potential hydrological corridors have been identified in Kenya and Tanzania, all four of them around Mount Kilimanjaro. To select the most promising corridor, a method was developed to support a decision in a situation where few data are available. The method is based on maps, models and literature from four different disciplines concerning soil, water, climate and social institutions. The findings favour the Tanzanian corridors and especially the Tanzania-East one, to start with re-greening projects. In that region many applicable land management options combine with a high potential for restoring soil organic matter, the highest rainfall recycling potential exists in the more favourable long rains season, while finally also the Tanzanian governments both at national and at local level seem more dependable for supporting hydrological corridor implementation.