The phenotypic traits of 63 Asian plum varieties were investigated for three years to select those with superior qualities for breeding. Eight morphological characteristics of the flowers and fruits (e.g., stigma position, fruit skin, and flesh color) were evaluated. Phenological characteristics (e.g., blooming time and ripening time) were also monitored. Being useful traits for breeding, fruit quality factors (e.g., fruit weight, skin color, flesh color, soluble solids content, and titratable acidity) were evaluated as well. The majority of the fruits were cordate (36%) and circular (23%) in shape. Approximately 78% of the varieties showed a red skin color, whereas 67% had yellowish fruit flesh. Fruit ripening occurred from June 28th to September 5th, spanning 69 days. The average fruit weight and soluble solids content were 77.2 g and 12.2 °Brix, respectively. Regarding correlations among the characteristics, the most significant correlation coefficients were for the ripening time and fruit size parameters. Such information of Asian plum varieties will be useful for future breeding programs.