The ISLANDS project is implemented by the Indian Ocean Commission using the European Development Fund of the European Union to support the implementation of the Mauritius Strategy in beneficiary countries. This paper shares the experiences of ISLANDS in deploying system dynamics modeling in five countries in the Eastern and Southern African and Indian Ocean Region (Comoros, Madagascar, Mauritius, Seychelles and Zanzibar) for sustainable development planning. Lessons learned regarding the design and conceptualization of the project ISLANDS, including the adoption of system dynamics modeling as an integrated assessment tool for policy planning, are discussed. Although Madagascar and Zanzibar are not defined as small island developing States (SIDS) in the UN System, the lessons learned from these countries are applicable to all SIDS. The approach used by ISLANDS for technical assistance consists of nesting learning-by-doing, multi-stakeholder processes, and dedicated capacity-building in system dynamics modeling, as well as advocacy for the integrated modeling tool with decision-makers. While island developing States are recognized for their inherent vulnerabilities to shocks, the adoption of system dynamics modeling helps to achieve policy-induced resilience by exposing the challenges and constraints posed by the lack of reliable statistical data. Institutionalization of the tool is progressing well in the region.