Cultivated European grapes commercially spreads in the world but East Asian wild grape germplasms have been left standing without any studies on their nutraceutical potential. To date, there has been no report on the characterization of phenolic compounds in wild grapes native to East Asia and their hybrids. Hence, the aims of this study were to evaluate and characterize the phenolic composition and antioxidant activities of the berry skins and seeds of five wild grape germplasms native to East Asia, particularly Japan, two hybrids derived from wild grapes and the related cultivated grapes. The present study demonstrated that the berry skin of wild grapes contained higher amount of total phenolics compared to those of V. rotundifolia and V. vinifera cultivar. By evaluating wild grapes, we may be able to assess the value of these indigenous natural resources and promote their cultivation once the nutraceutical benefits have been identified.