Foran, 28, has scored twice in six appearances for the Quakers during his first month at the Darlington Arena but will now remain with Dave Penney's side until January 5.
Foran, who has not played for Steve Tilson's Southend side so far this season, also had a loan spell with Darlington last season.
The Shrimpers paid Motherwell £150,000 for Foran's services in January 2007 since when he has scored only twice in 23 appearances.