Countries in the Northeast Asian subregion have made significant efforts to shift theirdevelopment patterns to being more sustainable, but a number of challenges still remain. Perhaps the most basic challenge for each country in the subregion is the development of a further concrete and integrated national sustainable development strategy (NSDS) addressing challenges mentioned above. Elaboration of truly integrated sustainable development strategies based on comprehensive ecological viewpoints that fit into their national contexts, taking both long-term environmental and socio-economic implications into account, as well as paying attention to strengthening its implementation mechanisms, is vital to each nation in the subregion as well as to the subregional development in sustainable manner.