A convoy of 12 barges carrying some 3,220 people left Kosti, in the Sudan, ten days ago and it is expected to reach Juba by Sunday.
The returnees are using four passenger barges and eight luggage barges, the UN said.IOM, the International Organization for Migrations, is already making reparations for another movement of some 3,000 returnees from Kosti to South Sudan.
The loading of luggage is already underway and the convoy should leave Kosti within one week.
The movement of returnees to South Sudan is gaining pace again now that the end of a period of grace for Southerners living in the Sudan is approaching on March 9, 2012.
Last week more than 2,000 people arrived in Aweil and Wau from the Sudan by train.
The UN says that since the end of October 2010, over 350,000 people returned to South Sudan in organized and spontaneous movements.