The border follows this river briefly down to the Shatt al-Arab, the thalweg of which it then follows out to the Persian Gulf at the "lowest point of low water" at the mouth of the Shatt al-Arab at  (WGS84).
The border follows this river down to the Shatt al-Arab and then traces the thalweg out to the Persian Gulf at its lowest point of low water at the Shatt al-Arab's mouth, as defined by (WGS84).