Papilio iswara has large black wings with white streaks on the forewings and white patches that extend from veins 4 to the apex of the hindwings. The female butterfly has black eye-like markings surrounded by dark red in spaces 1 and 2 on the upper side of the hindwings. The size of the female is larger than the male. This species has a large, thick, spatula-shaped tail on vein 2.
Larva: Papilio iswara larvae are cylindrical, green in color with 2 transverse lines on their back.
Pupa: Papilio iswara pupae are brown in color.