Small Island Developing States (SIDS) are constrained by their size, isolation, natural vulnerability and limited natural and financial resources. Freshwater resources, limited to groundwater in many cases, are exposed to extreme weather events, threats to water quality and increased exploitation due to increased water demand. Access to sanitation and safe drinking water, protecting the sensitive ecosystem and generating productive use of variable water resources are among the main challenges small island countries are facing. The challenges require innovative approaches and tailoring of solutions to the complex combination of geographical and socioeconomic constraints of an individual island.