The Hornets almost signed the centre-back last summer when he left Tottenham following six years in north London.
Sunderland ended up landing the Frenchman though, but now he could finally be set for a move to Vicarage Road.
Indeed, according to L'Equipe, Walter Mazzarri's side are on the cusp of signing Kaboul after holding talks with him for over a week.
The 30-year-old is ready to sign a three year-deal with Watford and negotiations over a transfer fee are underway.
Kaboul still has three years to run on his current contract at Sunderland and the club are hoping to bank around £4million from his sale.