Among the impacts of global warming, sea-level rise (SLR) poses the greatest threat to the stability of human habitation along coastlines. Areas along coasts and rivers have been affected by SLR, underscoring the need to assess the vulnerability of coasts and the effectiveness of riverbanks. It is therefore necessary to develop countermeasures to mitigate the influences of strong and persistent SLR for coasts and river levees. Among the options available for countering these threats, the application of geosynthetics is a promising strategy, not only for coastal structures but also for river levees that are affected by wave action, which is sometimes severe enough to produce storm surges. Geosynthetics are designed in accordance with natural, social, and economic circumstances of the region. For example, low-cost construction materials such as jute and palm tree fiber are available as natural geosynthetics for the construction of infrastructure where greater strength and resilience are needed. Artificial geosynthetics must be selected to meet the requirements of each infrastructure project. This report presents a proposal of a procedure for selecting natural and artificial geosynthetics, particularly for adaptive measures against increasing erosion and inundation attributable to SLR. In addition, the report presents a discussion of the application of traditional and advanced geosynthetics as adaptive measures against coastal and river erosion even when severe earthquakes strike coastal areas.